Again, went on sorties isn't the same as having numbers of flight hours in a combat helicopter, especially in war time situation. That's a hell lot of valuable experience and know how that would be beneficiary for LCH development and it's simple logic. You can stick with your believe, but obviously can't really argue against it.
Secondly, the attack helicopter deal is for IAF not for IA, so far there is no statement that the deal will go to IA and imo it doesn't even need to go to IA, since they will get Rudra and LCH in high numbers anyway and for the fire support role. No need to waste billions of money that could be spend more wisely (especially in IA), just because they want a something foreign or what initially was meant for IAF.