Why does the "Exceptional" Holiday Case item (Giant Tree) only give 630 happiness?

[Supervolcano]

Here's the Holiday Case items we've seen so far:
Igloo (common) - residence - 300 population (1 space) - Sell for 1000 Coins
Frozen Mammoth (common) - decoration - 360 happiness (1 space) - Sell for 1200 Coins
Huge Snowman (common) - decoration - 450 happiness (1 space) - Sell for 1500 Coins
Winter House (small) (common) - residence - 540 population (1 space) - Sell for 1700 Coins
Winter House (large) (common) - residence - 600 population (1 space) - Sell for 2000 Coins
Hockey Rink (uncommon) - decoration - 750 happiness (4 spaces) - Sell for 2500 Coins
Skating Rink (uncommon) - business - 900 happiness (4 spaces) - Sell for 3000 Coins
Winter Workshop (rare) - business - 1440 happiness (4 spaces) - Sell for 4800 Coins
Mountain (?rare or exceptional?) - decoration - 2040 happiness (16 spaces) - Sell for 6800 Coins
Giant Tree (exceptional) - decoration - 630 happiness (4 spaces) - Sell for 2100 Coins


So why does the hardest and most prized Holiday Case item only give 630 happiness?

This is inconsistent with how the Magic Case, Halloween Case, & Amusement Case work.
The exceptional item from those gives the most happiness.

Here's the screen shot of it's "1st Key" exceptional rarity:

[Supervolcano]

Here's the Magic Case items we've seen so far:
Wind Farm (common) - business - 300 happiness (1 space) - Sell for 1000 Coins
Adobe House (common) - residence - 450 population (1 space) - Sell for 1500 Coins
Ice Cream Store (common) - business - 600 happiness (1 space) - Sell for 2000 Coins
Small Skate Park (common) - decoration - 600 happiness (1 space) - Sell for 2000 Coins
Luxury Condo (uncommon) - residence - 750 population (4 spaces) - Sell for 2500 Coins
Fancy Condos (uncommon) - residence - 900 population (4 spaces) - Sell for 3000 Coins
Big Ben (rare) - decoration - 1440 happiness (4 spaces) - Sell for 4800 Coins
Saint Basil's (rare) - decoration - 2040 happiness (4 spaces) - Sell for 6800 Coins
Burj Al Arab Hotel (exceptional) - business - 2880 happiness (4 spaces) - Sell for 9600 Coins


Here's the Halloween Case items we've seen so far:
Scary Tree (common) - decoration - 300 happiness (1 space) - Sell for 1000 Coins
Crashed UFO (common) - decoration - 450 happiness (1 space) - Sell for 1500 Coins
Creepy House (common) - residence - 450 population (1 space) - Sell for 1500 Coins
Halloween House (common) - residence - 600 population (1 space) - Sell for 2000 Coins
Pumpkin Patch (uncommon) - business - 750 happiness (4 spaces) - Sell for 2500 Coins
Graveyard (uncommon) - decoration - 900 happiness (4 spaces) - Sell for 3000 Coins
Monster Attack (rare) - business - 1500 happiness (4 spaces) - Sell for 5000 Coins
Haunted Mansion (rare) - residence - 1800 population (4 spaces) - Sell for 6000 Coins
Grim Tower (exceptional) - business - 2880 happiness (4 spaces) - Sell for 9600 Coins


Here's the Amusement Case items we've seen so far:
Small Colonial House (common) - residence - 300 population (1 space) - Sell for 1000 Coins
Merry Go Round (common) - business - 450 happiness (1 space) - Sell for 1500 Coins
Large Colonial House (uncommon) - residence - 1050 population (4 spaces) - Sell for 3500 Coins
Pumpkin House (uncommon) - residence - 1050 population (4 spaces) - Sell for 3500 Coins
Ferris Wheel (rare) - business - 1800 happiness (4 spaces) - Sell for 3000 Coins
Roller Coaster (exceptional) - business - 2700 happiness (9 spaces) - Sell for 9000 Coins


Here's the Holiday Case items we've seen so far:
Igloo (common) - residence - 300 population (1 space) - Sell for 1000 Coins
Frozen Mammoth (common) - decoration - 360 happiness (1 space) - Sell for 1200 Coins
Huge Snowman (common) - decoration - 450 happiness (1 space) - Sell for 1500 Coins
Winter House (small) (common) - residence - 540 population (1 space) - Sell for 1700 Coins
Winter House (large) (common) - residence - 600 population (1 space) - Sell for 2000 Coins
Hockey Rink (uncommon) - decoration - 750 happiness (4 spaces) - Sell for 2500 Coins
Skating Rink (uncommon) - business - 900 happiness (4 spaces) - Sell for 3000 Coins
Winter Workshop (rare) - business - 1440 happiness (4 spaces) - Sell for 4800 Coins
Mountain (?rare or exceptional?) - decoration - 2040 happiness (16 spaces) - Sell for 6800 Coins
Giant Tree (exceptional) - decoration - 630 happiness (4 spaces) - Sell for 2100 Coins


Here's the odds for the virtual dice roll that decides which random item you'll get:
54% chance you get a Common item.
35% chance you get an Uncommon item.
10% chance you get a Rare item.
1% chance you get an Exceptional item.


Here's how Population or Happiness Value can be obtained:
1. Place the item where you want it in your city.
2. Check your Profile and note your current Population & Happiness Values.
3. Hide the item back into your inventory.
4. Recheck your Profile and note your new Population & Happiness Values.
5. Subtract step 4 from step 2.
6. Place the item where you want it in your city.


The Sell Price appears to follow these patterns:
You receive 10% of the purchase price when you sell any item bought with Coins.
You receive 100 Coins per City Cash spent when you sell any item bought with City Cash.
You receive 100 Coins for every 30 Pop/Happy when you sell any of the "Special Case" items.