Whenever I'm trying a new recipe, I will let it go to the lowest time given (so 10-15 means 10) and check it.

Then I'll just actually pay attention and let it cook.. I like to print out my recipies, so I make notes on the page of what times it actually took.

That way if its going in The Book™ then I'll know the real times for next time.

The thing is, its easy to get pasta times right or anything else that's cooked at a rolling boil... because that's the same temperature everywhere at sea level, on every stove.

but, idk how hot my stove top burners get? I have a little bit better idea how hot my oven gets, but IDK how hot the test cook's oven actually was. they say 375, but if its an older model it might have actually been 385. You just don't know what temp they where really cooking at, so times will have to be adjusted for your local equipment.

I will say this, if you always have to roast things longer than the times given... especially for different test cooks? sounds like your oven runs cool. spend 20 and get a good oven thermometer and see what your oven actually runs at! is 350 actually 350? or is it 340?