Hi Oz, I know plenty are doing it so take this for what it is(specualtion by someone that's not doing it).
If all post jetted passages(from the d-block jet out) aren't exactly equal(in all ways), then the metered amount will not be distributed the same.
Look at putting a jet before a 4 outlet shower head and then running those four lines to each cylinder with four exact same lines. If there's even the slightest more restriction(say more bend?) in one line then there are in the other 3, the others will have higher flow(and with less projection), although the difference at these sizes might be insignificant(?).
I wanted to make sure I was thinking about this correctly, so I just used the same scenario with about 20% bottle pressure(175psi), and at least in my("how far and how fast can I blow the assembly lube bottle across the floor" and my "back of the hand pressure") comparrison tests, it seems like there is enough difference to matter.
Now as long as you tune each cylinder via AFR and EGT seperately once set up, then you should be fine no matter what.
Looking forward to a more experienced answer myself(figured this might kick the ball though)... good question!
Todd