As nobody wanted to guess , I give you the result:
Broker 2 is Tradeslide (Darwinex), where people were/are complaining about swaps.
I can't recalculate these figures:
Yesterday (Tuesday) Broker 1 charged 9.0 EUR per Lot, while Broker 2 charged 5.3 EUR per Lot for a short position.
None of them had the 3-days swap on Tuesday.
What's visible in MT4 is not used for the swap calculation on the account slip.
Traders should know that (and usually complain about the account data, not the MT4 data).
Algo-Traders using the MT4 data might get wrong results.