G'day folks

I imagine this question has been posted many times before although I couldn't find any reference to it.

In Quark for copyfitting I used to track out to a maximum of 2 (or sometimes 2.5, don't tell ;) ) and track in to a maximum of -2 but in indesign it seems to be different. My feeling is that -10 in indesign is the equivalent of -1 in Quark and -20 of -2. Is that correct or am I crazy? Certainly these values seem to have a similar effect.

I would appreciate any help