Whenever a pooling plan is in effect as provided in Chapter 3 (commencing with Section 62700) and Chapter 3.5 (commencing with Section 62750) of this part, all market milk received by pool handlers shall be obligated to the pool at the applicable minimum price established in the Stabilization and Marketing Plans based on the classified usage of that milk. Handlers may pay producers for restricted use market milk at prices that are less than the amount credited to those handlers for restricted use market milk by the pooling plan.