The exhibit CLIN structure approach proposed within your question is certainly permissible by the regulations and accepted by DFAS.  

But I did share your question with a few of my peers and reached out to DFAS as well.  I'd categorize their feedback as cautious.  Using an exhibit does present more opportunity for error if the payment instructions aren't clearly understood or followed exactly.  Additionally, depending on how you distribute the lot price, an  ELIN can undermine the Government's mandate regarding the integrity of unit prices and balanced pricing.  So from a contract administration perspective, the safest approach would be to take the time and create separate CLINS. 

DFARS 204.7103-1(d) Exhibits may be used as an alternative to putting a long list of contract line items in the schedule. If exhibits are used, create a contract line item citing the exhibit's identifier. See 204.7105.