Difficulties finding the actual date of a paid bonus

According to this help article (https://support.personio.de/hc/en-us/articles/360000406509-Create-and-manage-bonus-payments) there are two types of bonuses - I'm interested in the variable bonus. It is mentioned that you set an effectiveFrom date and then you manually add the payment in the respective bonus column. In the Personio GUI I can see the bonus appearing correctly in the salary tab.

Now pulling those two exact compensation entries through the API (https://developer.personio.de/reference/get_v2-compensations) I'm getting this (formatted for legibility):

id= person= type=nil category=BONUS_PAYOUT amount=4000.0 EUR effectiveFrom=2015-01-01
id= person= type=nil category=BONUS_PAYOUT amount=5000.0 EUR effectiveFrom=2015-01-01

With this - how am I supposed (by just using the API) to tie one specific API response to an actual year since I'm only getting the same effectiveFrom (which by the way is the start date of that very employee)?