Do you mean the operators' MEL, or the manufacturers MMEL, from which the operator may make his (sic) own MEL.
Sometimes operators add their own restrictions to suit their own
operation and previous operational experience.
If for example,an operator has had an aircraft skid off a wet runway when a reverser is 'locked out', that would represent a costly occurrence, so the mel is re-written to protect the operator
from risk exposure,'bolting the stable door after the horse has gone'.