Is it really quicker to cut the block in half rather than walking back?

I used to park my vehicle in the middle and cut the mail in half on heavy days as taught by my trainer, but then I have to fumble trough the DPS, marriage mail, flats, and SPRs and cut them all in half. Now I've just started to just walk back to my vehicle and it takes about 5 mins max walking back and forth to pick up my second half of mail. If it's still heavy, then I just treat my SPRs as parcels.