John Franklin-Myers both smiled and shrugged when asked about the NFL admitting to the Jets that his costly roughing-the-passer penalty last Sunday against the Cowboys was an incorrect call.

Franklin-Myers said he knew he was “in the right” when flagged for a hit on Dak Prescott in the second quarter that kept a Dallas touchdown drive alive.

“It’s cool. But it’s kind of like, to me, it doesn’t even matter one way or another now. It’s too late now,” Franklin-Myers told The Post after practice Thursday. “It’s all hindsight now, in the past.

“It’s cool that maybe it will change something for the future, but I knew I was in the right when it happened.”

The Jets were trailing 10-7 with two minutes remaining in the second quarter, when Franklin-Myers appeared to hit Prescott above the knee as he released the ball on a third-down pass for an incompletion.

The penalty enabled the Cowboys to go in for a touchdown, extending the lead to 18-7.

“As I was falling and being pulled down, I really tried to make sure I hit him above his knee,” Franklin-Myers said. “I knew I hit him above the knee, but I was like, ‘Dang, maybe I don’t know the rule or something.’ But everyone was like that hit was right.”

The fifth-year defensive end also had been called for a key penalty for roughing the passer last season against the Patriots, the Jets’ opponent this Sunday, negating a pick-six by cornerback Michael Carter II.

Franklin-Myers added that “the toughest part” of both calls were “the impact they had” on the scoreboard, but he doesn’t hold that flag against the officiating crew.

“Football is such a reactionary sport, and that ref has a job to do,” said Franklin-Myers, who has one sack and three quarterback hits through two games. “He came up to me after it and said, ‘That was just my judgement at the moment.’ If that’s what he thought, then he ain’t in the wrong, and he can justify himself.

“It’s part of football and as long as we understand that, and just me being able to get that opportunity to hear that was good. But also to hear from my coaches about what I can do differently, that’s all I can take from the whole situation. I know I can’t slow down as a football player. I have to go out there and do my thing.”

Defensive coordinator Jeff Ulbrich said the league’s admission was “no consolation” beyond reinforcing that the coaching staff is “emphasizing the right things” to the team.

“Based upon the rules I know that’s not a penalty, [Franklin-Myers’] face mask hit Prescott on the butt cheek,” Ulbrich said. “Everything in the rules say knee or below, so it’s a little frustrating from that standpoint, but that is part of the game.

“Good calls and bad calls are always part of the game. You’ve got to overcome that. Unfortunately, we didn’t, but I disagreed with the call, for what that is worth.”