Always be up front. It’s just an infringement - two printouts, wring mode selected, keep one, give them one, sign a bit of paper at some point and on you go. Everyone makes mistakes and that.
But by sounds of it you get deducted breaks? Then you go on ad it looks like you’re trying to get that time back? Might be wrong but its early and thats how it comes across to me. Thats more of a sticky wicket, a deliberate act, which is less defensible.
I guess honesty is the best policy and you’ve made a mistake so it might cost a bit.