hehe, yes @nomad-magus I´m on your side, you got the right thoughts, but usualy pro rata means they will split the long lasting positions in some shorter ones, maybe weekly or monthly to get rid of them.
The math behind is quite simple in my eyes, the LP-mining was calculated for a total sum at the end, so they only have to divide it by the number of days (eg. 30 / 90 / 180 / 270 360 whatever was the term for this stake), multiply it with the days what the coins lasted in the liq-mining-pot and then they have the amount what´s it worth today or tomorrow, a smple spreadsheet, its every day the same amount.
But dont expect the whole amount what was calculated until it matured like they call it.

For instance when you have a pos. in the 12 month and now you have 3 month done and they will pay it back in 14 days, you will normally it like that (promised endsum / 360*days until payout), for instance if 120,000 WOX was the target sum after 12 month we have 120,000/360=333,333 *104 (3x30+14 like given above)=34,,666.6666 Wox ;)