Mix match currency symbol or list price with make an offer plugin

Hi there,
we have a plugin which is enable customers to make an offer
here is the issue.
our default currency is GBP
the other currency is USD and EUR

Issue: If one makes an offer in USD or EURO
eg if product is £ 3850 = $ 5198
and exchange rate £ 1= $1.35
the amount registered at the back end should be $5198
but rather changes to $3850 which completely wrong.
this problem happen only if the customer is not is from default currency GB country or zone.
test link. https://thefmgallery.com/product/pair-of-vintage-brass-shape-leaf-wall-lights-by-tommaso-barbi-2/
https://www.dropbox.com/scl/fi/o9vthodd1zto38bj6yh5a/Screenshot-2026-04-03-at-09.34.47.png?rlkey=ejv5wk6bdret30idra5h6ru4h