Update:
Have about 5000 miles on the Gates 18423 (Heater/PCV) hose so far, and running great.
Contacted Gates after installing the 18423 hose and they said even though this hose was not designed for PCV applications, it should not crack, but might get soft with time.
The OEM hose had probably been cracked long before I discovered & replaced it. The car runs & idles great, and no more engine check light/lean code.
