Hello Werbil:
Although I don't doubt the sincerity and good intentions of your chief pilot, I have a lot of concern about how much credibility gets attached to "My grandpappy told me that..." and "My chief pilot heard it from an instructor who heard it from someone else..." type of anecdotal comments.
I'm a pretty simple guy, I only read the black ink in the manuals. Pratt & Whitney has made over 50,000 PT6A series engines now, and if they thought that the starting temperature limits needed to be lowered, they would have lowered them. They have not done so, and the starting temperature graph is pretty simple to comprehend - for a -27, temperatures as high as 925° are acceptable without time limitation during a start.
As I said before, if an engine normally peaks at 600° when starting, and suddenly, without apparant justification, the T5 takes off heading well north of 600°, sure, it would make sense to abandon the start attempt. My point, though, is that if we know before we even engage the starter that the start will be warmer than normal - either due to retained heat in the engine, low starting voltage, or some other abnormality - then we should have sufficient comprehension and understanding of the published engine limitations to know that a higher than normal start temperature is not, a priori, a problem.
I guess what gets me going on this soapbox is that I have seen so many examples of accidents or near-accidents caused by pilots who do not comprehend engine limits and instead rely on hand-me-down folklore. Consider a Twin Otter, for example: It has a 680 HP engine that has been flat rated to 620 HP for airframe reasons (not related to the engine). This means that a 50 PSI torque takeoff - that being the redline on the engine - is only demanding 91% of the power that the engine is designed to produce. But, how many times have you seen someone take off (at ISA) using only 45 PSI torque, because they think that doing that will somehow "be nice" to the engine, or lengthen the TBO or the time between hot sections? Truth is, it has been well demonstrated that such actions do not increase TBO or time between hot sections, but they do greatly increase the liklihood of accidents, due to longer ground runs or less than adequate single engine climb performance.
As professionals, we need to be critical of what information we give credence to. Like I said, I only read the black ink in the manufacturer approved publications.