I'm not endorsed on the Van, nor do I have experience with that particular PT6 (plenty with the -67 and -42).
However.... I agree with Blatant. It sounds like Cessna put that mark on the guage so that Joe Blogg's with 200hrs could fly a Van. Keep it simple maybe.
If the ITT, normal engine torque and NG haven't been exceeded, then have they really had an engine exceedance by going past that 'climb torque'?
morno