Delta Interchangability 1300 vs. 1700

In my condo, I have a Shower/Tub & a Shower, both with Single handle Mixet valves which control Temp & Volume. It was only after replacing my waterheater, that I became aware off the the Mixet crossover issue which I suspect was wasting energy by backflowing my hot water heater. So to resolve I first replaced the Shower/tub with a delta 1354. This model unfortunately does not offer volume control (apparently very few do), which I thought would be ok, but after washing my dog, I really need to control volume.

My question is this: Does anyone know if the Delta 1354 Rough-in (the brass contraption) is any different than the Delta 1700 Series Rough-in? In other words, are the valve Cartridges interchangable? If so, then I would be able to buy a Delta 1700 series, use rough-in for my Shower and Swap Valve Cartridges with my 1354 Shower/Tub. I hope this makes sence.

Delta

It can't be done. The pressure balancing function is performed differently in the two valves so the internal length of the two "cartridges" is different.

Thanks for the info

It was worth a shot.