So far have found Papagayo/Perch charging just over the bank exchange rate even for cash. Papagayo gives the bill slip showing either euros or higher amount in dollars. Last lunch there was Nov 8 and rate was 1.10.
Ate at Rancho up on the hill last nite and cash was 1 for 1.
I recall La Piment was 1 for 1 when we ate there last Sat.
Other small establishments/grocers we have been to have been 1 to 1 for cash. Euro rate for cc charging.