The DPP's have a far greater failure rate than a DP twin. It makes no sense to use a DPP and then use a DP44. Even if you purchased a DPP, take it to a local dealer and work out an exchange for a DP-twin or quad. A DPP has value to a dealer, wereas most of us have boxes of twins laying around.
If you can run two cables to your 622 (or 625), you can use your existing legacy quad.