Last year at this time, YSS (HousesHitter) turned 18 and the Girhippo was in an all fired hurry to have him removed from the CS roles even though CS goes to 21 by law here in good ol' BM-centric NYS.  It was always a puzzlement to me just why the Gir would want to refuse extra CS.  Well it occurred to me that tax year 2021 is the year of the "advanced child care credit" and that she had long before, signed that year to claim YSS for the last time over to Chef (form 8223 signed by her back in 2015).  2015 was the year when Chef FINALLY got a lawyer who slightly rectified all the abuse of the original MOU included in the CS order and divorce papers i.e. only claiming the oldest child and she was claiming both younger children.   This agreement forced her to rotate the two youngest for tax claiming purposes.

She'd be gaining an extra $6,000 for the 2021 tax year as a credit if Chef had CS ceased retro to YSS's 18th birthday.   There's no way he's going to college so no one can claim him anymore through age 21 as a student, either.    Chef only recently had the other two come off the CS grist mill and so his monthly payment is now less than what his WEEKLY payment used to be back in 2004/2005.