Level of building doesnt increase drops. Get over it. Its a fact

[burritosprings]

Its truth and prove me wrong if u wish

[dangerb0y]

Wizard school and bountiful table off the top of my head

[GarfieldandPookie]

Oh snap

[ryusei745]

Any of the resource buildings that upgrading decreases the time it takes before you can collect technically DOES increase how much you get but not necessarily quality. But as it is still more chances at the rare items you are indeed more likely to get it.

Does lvl 5 library/jeweler/whatever have higher chance for books/jewels? No.

Does level 5 deep mine give you a better chance for mithril or adamant? No. but it gives you more chances because you are able to collect from it every 8 hours instead of 10 ish.

The only building where it could be said your chances improve with each upgrade are the upgrades that make them take less time to recharge before the next collection.

And wizard schools as they do drop more with each upgrade in addition to taking less time, yeah they drop more energy with each upgrade just like all of our royal buildings drop more coins with each upgrade.

Yes bountiful table drops feasts at lvl 5. Just like harvest pergola, reindeer stable, and kingdom inn don't drop their specials drops until they are completely built.
Those are the only exceptions to the rule that upgrading does not increase odds of drops, but with those buildings it's more like there are NO special drops until it is level 5. Adding drops at max level =\= an increase in chance of recieving rare items