DP and pitcher swap

Question
Hi, my name is Joe and I coach/manage a team in a Mens modified/fastpitch softball league.(any pitching style is allowed except for full revolution 'Windmill') We use ASA modified rules. My question is this: When using a DP(designated player) to hit for the pitcher, can the pitcher and the DP swap places every other inning? They would share the same spot in the batting order through out the entire game, with one of them hitting if the other is currently pitching.We use a DP and an EH(extra hitter) as to get more players involved in the game.

Answer
Hi Joe,

A little confusing as you are adding stuff to the FP rule, DP, Flex, and EH.  I don't normally answer hybrid rule questions but in this case I'll try.

I assume F1 is the Flex (in your case 11th on the line-up card and does not bat).  The answer is no, when the DP pitches, (plays defense for the Flex) the Flex comes out of the game and may re-enter once.  If the FLEX bats for the DP, the DP is out of the game and may re-enter once.  You can't have Flex pitch, DP bat, DP pitch, Flex bat and so on and so on, if that is what you are asking.

Mark