If you are wearing clothes with a bonus towards money and exp when you turn up to a job and look at the stats, these bonuses will be taken into account. If, when you put on the best clothes for a job, they don't have those bonuses, you'll get more pickaxes potentially. Start the job with the best clothes on, then change into gear with bonuses and you'll get your best return with the bonuses calculated when the job ends.
I think @Dilligan is right, you changed from a %bonus to a +LP bonus.
Use your work clothes first to queue the job, then change to % clothes, your pickaxes stick when you start the job and you can get extra exp and cash (also luck if you have the bonus) at the end this way