Standard for 3 features should be $103.56 for 30-day months ( excluding base 0.05% - which is near $3 monthly ), and $107.01 for 31-day months.
Basically 1.8% bonus plus 0.05%
Layers probably has extra bonus interest from Wealth Investment factor, etc
Yes, on top of the standard 3 bonus, Layers has got that extra 1.2% from Wealth bonus. Adding the 4 bonus with the base 0.05% interest, final bonus is $175