I'm not getting the correct donuts for merging

There are two reasons why player think they aren't getting the correct number of Donuts for their merge actions in the merge game. 

1. Merging cash, coins, and energy bundles won't earn you any donuts. 

2. Merging items quickly, one after another, will combine the total Donuts earned from all the merges. For example, instead of receiving 2 + 4 + 8 + 16 separately, you'll get 30 in one go, with only a single increase in your Donut bar.