Given that the must common causes of failure to end cycle are related to bells and whistles (aka moisture-sensing, etc.) and further given that timers generally are pretty robust, I'd tend to guess that's why you don't see it suggested.
But from your description, that's where I'd be focusing my attention. I'm not familiar with that specific model, but I can't come up with any other explanation for why the timer wouldn't advance to end of cycle in timed mode. It's worth at least pulling it out for an inspection to see if there's something obvious, dirt and lint do get everywhere in dryers.

Good luck.