Resource Balance is not getting created for Future dated purchase of product

Hi all,

Using  PCM_OP_SUBSCRIPTION_PURCHASE_DEAL opcode, I am trying to purchase a product in future. That is achieved by setting the PURCHASE_START_T,USAGE_START_T and CYCLE_START_T fields to future dated value (Relative time-stamps) and event's END_T is present system time.

My question : Is it advisable to use the above method or we should use /schedule to accomplish this ?

Next question : If the above method is fine, then the product's rate or resource(if available) should be automatically applied on the set future date. Is that correct ?

For Eg :  I am purchasing a product A, with