Hi Siraj,
If you sell to your AE at a discounted price, there is no doubt you will be in trouble at TPO level;
And there is no limit for applicability of TP as it is applicable on each & every international transaction between the Associated Enterprise.
However for maintenance of books & records there is a threshold limit of Rs. 1 crore.
You cannot justify this transaction without charging any profit element.
If you are selling the same product to non AE, then it is advisable to charge the same rate to AE also which would be compared at CUP.
If you are not selling this product to any other than the AE, then it is advisable to get the market rate and charge accordingly.
Regards
Ramesh