ACU and other ratings can be miss-leading, especially when they only include 20 or so - usually final - votes, as he may vote against or delay a bunch of budgets or resolutions that would have otherwise been more conservative than the final bill. A lot of conservative ratings tend to rank more on chamber of commerce POV rather than mainstream american conservative as well.
That’s true. There’s a FReeper here who averages in several groups from left and right to distill a “truer” rating. Still, I find the ACU tends to get about as close to the average in figuring out which are to be trusted and which aren’t.