When to replace Timing Belt

[FlaAveo5]

The service interval changed in the 09+ model year (2nd gen) to 100k. 08 and earlier are still 50k-60k.

And the US engine DID change in 09 to the Ecotec whereas the 08 and prior used the E-tec 2. The most noticeable change, that might partially explain the interval change, was that the water pump was removed from the timing belt loop and placed on the serpentine/accessory belt.

The plastic cover that is covering me engine says on it ' E-TEC II 16V', Not 'EcoTec' so that means it is the 60K mile engine? I ALWAYS thought it was called an 'Ecotec 16V' engine. So I have the crappy one...right?

BTW, i might as well ask you and anyone that sees his post/replies,....with only 33K miles on my engine, thought I was at 35K....is it TIME or MILEAGE that determines the replacement?? Do you or anyone know??. I posted a LONG reply/question to the Chevy lady that is in here...Victoria? And flat out asked why 'we' owners of the same engine on earlier models, get screwed out of that 100K mile replacement ,why doesnt Chevy give us a 1 time replacement of the belt and pump,etc...with maybe upgraded parts, or even the same poor designed parts, or extend the warranty on the belt/water pump till 100K .Waiting to hear if she will EVER reply. I know it will be "NO you get screwed haha!"
But i asked. So...do you or anyone know about the TIME VS. MILEAGE replacement issue that is on my mind all the time?