Two calculators are allowed at competition. Official rules clarification (FAQ, whatever) here
When talking about templates, I think of them like lasers in Trajectory last year (but let's not go down that path). Really, I think they're completely unnecessary, remove any challenge at all from the actual target test, and should be disallowed. There's nothing in the rules that really suggests that they should be allowed, anyway.
Since all teams have the option to use them, there really is no unfair advantage. I just don't see why they should be allowed.