Network fees are calculated based on mempool.space's priority fee. Can you share an example where you felt they were not correct?
Also you might want to check out Liquid swaps. We launched these recently precisely because of spiking network fees on the mainchain:
https://blog.boltz.exchange/p/launching-liquid-swaps-unfairly-cheap
On my node high priority is about 4000 sats, but you are charging 10000 in network fees in addition to 5000 Boltz fees. Maybe your service calculate it differently π€·π»ββοΈ 
Atomic Swaps consist of *two* transactions (first lock, then claim) and size might be slightly different from yours. Here is how we calculate size: https://github.com/BoltzExchange/boltz-backend/blob/master/lib/rates/FeeProvider.ts#L30
Oh I see. Thatβs why is 3X more than expected. Gotcha
