Taxes would explain it
Looking at a hotel in Madrid for example, rate includes 10% VAT
Exchange rate for EUR-USD according to xe.com is 1.226
EUR1.00 inc VAT = EUR0.91 exclusivg of tax
EUR0.91 = $1.12
so should be earning about 11 points per Euro
I suspect that the exchange rate used by IHG isnt quite as good as xe is listing so would be slightly lower