Here we go- another property with this cryptic 12.95 Erf PER NIGHT - and they classify it as a "tax." I am going to assume this is the same ownership:
Holiday Inn Express
475 W. Parkcenter
Boise, ID
Given no other IHG properties in Boise have this as a "tax," I don't think it is a tax. Also interesting this property's IHG quote does include this fee in the total for the stay. I've stayed in this property in the distant past and none of these fees were going on then. 2 night stay
Nov 7 - Nov 8 130.50 USD
Nov 8 - Nov 9 148.50 USD Additional charges
Cc Surcharge
8.38 USD Taxes
2 Pct Lodging Tax; 6 Pct State Tax; 5 Pct City Tax, Usd12.95 Erf
62.18 USD
Total price349.56 USD