Koroisau's bid to win a recall for NSW's State of Origin side hangs in the balance after the hooker was sin-binned for a possible hip-drop tackle and placed on report for a dangerous throw by referee Ashley Klein in Thursday's 33-14 win over Canberra.
Fijian international Koroisau has already been cited three times this season for dangerous contact and is staring at a ban if his name appears on the NRL's match review committee's charge sheet on Friday morning.
The Raiders scored their only two tries at Leichhardt Oval while Koroisau was in the bin as the Tigers recorded their fifth win of the season.
"The inconsistency of the referees is annoying me at the moment to be honest," coach Marshall said.
"I know we won but some of the calls … it's hard to understand.
"In Api's case with the sin-bin, I don't know what he's supposed to do in that situation.
"He's making a cover tackle from behind, of course he's going to land on his legs.
"There's heaps of things that didn't go our way, I just think the fans deserve some consistency around the interpretations of the rules - and we're not getting it."
If he had been on the field, Marshall claimed he would have challenged the decision to award a second-half penalty for a dangerous throw on Raiders forward Zac Hosking.
The Tigers outfought and outthought Canberra, who have won just three games all season and look a shadow of the team that claimed last year's minor premiership.
Halfback Adam Doueihi bagged two tries, kicked four goals and added a late field goal to push his case to be part of NSW's squad for the series opener on May 27.
Blues great Andrew Johns has pushed Doueihi's case because of the playmaker's versatility.
"It was his best game, impact wise, positioning, and where he played in the team," said Marshall, whose side face Cronulla and Melbourne over the next fortnight.
"Setting up everyone else and putting himself in the picture, kicking game, controlling the game.
"Andrew Johns is a pretty good judge of talent so if he's saying that, then yeah, put him in."
