Merrett avoided sanction for an incident on Sunday that left Melbourne's Cam Pedersen with a broken nose.
Leppitsch said he expected his rugged leader to be sitting in the grandstand for "maybe one, maybe two" weeks, but was pleasantly surprised when the MRP dismissed it.
He said changes were needed, with the system needing a more common sense approach.
"To a man, I think most people think the consistency is not there, mainly because it's based around points and less [around] common sense," Leppitsch said.
"I don't have the answers right now, but I've got a feeling it'll change.
"Sometimes the numbers just don't add up do they?
"When you're not dealing with human beings, case by case and common sense, when you're dealing in just numbers, mistakes can happen either way, for the good and the bad.
"I think that'll be reviewed at the end of the year."
Leppitsch said sometimes you were on the right side of the ledger and sometimes the wrong, and he knew the Lions dodged a bullet in having Merrett available for Sunday's match against Adelaide.
The defender-turned-forward was suspended earlier this year for an errant elbow on Gold Coast vice-captain David Swallow.
Leppitsch said there was no intent on either occasion, but Merrett had to fix his game up.
"For me, I know Daniel well, and that was extremely clumsy," he said.
"And even the one at the start of the year against the Gold Coast, it was the same, it was 'I'm late, what am I going to do?'
"You don't want to be clumsy at 105 kilos. He's done that a few times.
"I know Daniel; it's not born out of intent. If he had have used his right arm to spoil that ball as opposed to his left, we're probably not discussing it.
"There's some technique stuff in there as well that he's got to get better at."
Twitter: @AFL_mikewhiting
