lda to lmtp

Hi, Although dovecot-lda serves us fine, we only average 8k messages an hour, peaking at 11k, over 4 machines (mostly for redundancy, we've run this fine on just 1 machine, but sometimes clamav makes things get upset, so we added some more especially since we are growing rapidly, we decided to see if lmtp would be of benefit, so far, we cant tell any difference, I guess it is only 120-130 messages a minute, maybe if we were doing 200 a minute we might see gain?

The question is with lda we used postfix settings destination_recipient_limit=1, we have not added this with lmtp,is this needed?