10-15 seconds a day on a watch in that price range is acceptable. A quartz watch will be far more accurate unless you want to up your price point for a mechanical. I have several decent mechanical watches in the sub $300 range but none of them wii match the accuracy of a $50 quartz.
As a machinist, I assume you bought a mechanical watch because you appreciate what it takes to produce the movement. I will routinely take my watch off and just watch the gears and springs through the case back.
You have a good looking diver. Enjoy it
