Cash Management Interest

I’m trying out Cash Management for the first time (the free version). After a balance that was consistent for the whole month of November, the interest earned was lower than I expected. The interest earned was about .13% (.0013496). If I multiply that by 12 I get 1.6% (.0162). This is about half of what I expected for the yield (advertised as 3.12%). Am I missing some important information or making a wrong assumption? Does the interest fluctuate throughout the year and will make up the difference eventually? Thanks for your input.

i have stessa pro version. they just migrated to new accounts with a different bank. they closed the old accounts but part of the months interest is in the closed account.