It's both. If I wanted to I could write a document on it, browse the Interwebs, play Solitaire... The ladies who are using them only use them as tills, but that does not mean that they are not computers... Personally I don't think they should be counted, but I'd like to make sure.
I'm surprised that Gibson335 says none of his dinner ladies are FTE. Microsoft sets the bar very low and even those most fleeting of our staff do more than 200 hours per annum...