904 dual pumper

A few years ago when I had my /6 rebuilt in my 65 cuda, I had the tranny done also. The shop quoted me for a 904. When I picked the car up ( I didn't really pick the car up, I didn't want to show off) they said it had 2 pumps, 1 in front and another in the rear. Said they should have charged more for the 2nd pump but didn't quote it that way and only charged me what they originally quoted and still bedid the 2nd pump.

Said all that to ask, is there any advantage or disadvantage to this unit? From what I have be able to gather, the rear pump would allow the car to be pushed to start.

Thanks for any info. Tom