Im not sure if I completely understand....if you are sharing a reservation you must both be on the plan.
If you are not sharing a ressie, and one is on the plan and one has no meal plan at all then no, you can not share the dinner (I believe I have the policy correct on this)
If you mean that you will simply be short TS credits by the time you get to Narcoosees- that I dont know the answer to this, but I would this yes, you can share the meal since the plan allows for all under the same ressie to have the credits be interchangable.
ex: DH,DW and DMIL all on the same ressie. DMIL skips 2 TS meals, DH and DW could go to a TS with DMIL's credit allotment.