Tried HEL-AMS with KLM and Crowne Plaza Amsterdam City Centre and it works there too. Also tried Finnair flights HEL-WAW and the IC and worked. Did not work with LH flights HEL-FRA and HEL-MUC and Holiday Inns in those cities.

I must admit booking on exp is a pain. There are too many screens before you get to try the coupon.