That's in contrast to last season when 10 red cards were shown and arguably cost the club a crack at the play-offs – striker Roberts was sent-off twice and the team failed to win any of the five games he was suspended from.
Better behaviour on the pitch was therefore something the Latics manager was keen to see, and his players have responded when dealing with match officials.
Evidence of that was seen at Nottingham Forest on Saturday when Gareth Taylor scored Forest's controversial late equaliser in the 1-1 draw.
Despite the players' annoyance, there was no mass approach to the referee or his assistant in a bid to change the decision.
Jewell told the Evening Post: "If you harangue referees you get punished or at least you're supposed to, and I don't like to see my players do that.
"It doesn't matter what you think of a decision, it's what the officials think which count, and you're never going to get them to change their mind.
"There haven't been too many press conferences after a game when I have lambasted the officials, even if I think they are poor.
"It's not my style and I realise they do their jobs to the best of their ability, some better than others.
"On Saturday at Forest, I felt their lad was offside but we can't dwell on it.
"Running after the referee wasn't going to get him to change his mind and credit to the players for not doing so.
"Bookings are part and parcel of the game when it comes to tackling and things like that, but dissent isn't good.
"I spent too many games as a player sat out of matches because of talking back to referees.
"It's not clever or mature but it can take a lot of time before you realise it."
Jewell is content with his side's disciplinary record this season, although knows a couple of players still have to be careful over the coming weeks.
Roberts has eight bookings and two more before April 9 – the day Latics play at Cardiff – would land him a two-game ban.
Recent recruit Graham Kavanagh was red carded twice as a Cardiff player earlier this season and also has seven yellows to his name.
Jewell said: "Jason and Graham have to be careful because they've got a few bookings between them, so a couple more and they miss games.
"Kav would probably miss the rest of the season if he got another red card because his previous record is taken into account.
"Overall, our record on that score has been good this time.
"Only Lee McCulloch has been sent-off and I thought that was a bad decision.
"At this crucial stage of the season we need everyone available, not sat in the stand serving a suspension."
* Latics have sent Sunderland a 7,000 ticket allocation for the top-of-the-table clash at the JJB on Tuesday, April 5.
The game is expected to attract the season's best home gate so far.