id rather 4 larger injectors TBH (less chance of things failing and running lean on a cyllinder)
only possible reason i can think of with 8 inj plenums is spray distribution eg motune etc.
But i stand to be corrected
maybe back in the day there were no big enough injectors or management/mapping problems for them ?
EDIT miss read what you said but seeing as i mentioned spray pattern you might be correct with power delivery difference between the two