NFHS Substitution Question

[fastpitch]

Our HS season is just starting - 2007 NFHS rules.

Coach starts with 9 and Flex listed last and DP indicated. In third inning she substitutes for the Flex (#7 for #8) and tells me her DP will be pitching. I note the sub and asked her if she was sure she wanted to sub for the Flex. I also suggested she be sure the Flex is on the field playing defense. Next inning she wants the Flex to bat for the pitcher (#2) she removed (in her mind). She said I meant to substitute for #2. I explained she has already made a substitution for the Flex and the only way she can bat is if she enters the game for the DP. She says, "the DP is pitching, I took # 2 out." I told her she did not take #2 out, she simply had the Flex and DP playing defense at same time and that she could have any 9 of the 10 playing defense as long as the Flex is one of them. There was no argument.

Did I get this right according to NFHS? Would there be any difference in ASA?