This girl gave me 13 eggs a month on 6/5 and 12 eggs today.
Mine nearly always give me the first clutch 2 months after I take them out of brumation - I put them with the males right away - and give me the second clutch 4-5 weeks after.
This has happened more than 95% of cases, so I am inclined to think this means it is an automatic physiological process rather than her choosing when to allow it to happen. It could relate to the eggs developing in the two separate ducts.