Navy....
Thanks for the info... actually I was just using Desperado's scenario, whether my thoughts makes sense and general information when and if I ran into same scenario. Although your added questions should be considered whether to include it as a separately priced line item under the umbrella contract or procure separately would depend on the circumstances. If other items are closely related, I probably would try to negotiate the price of the items upfront (this of course if the other items would be required within the period of performance, maybe Desperados' scenario of within 8 months would not make a significant change in the price), determine fair and reasonable price, then fully fund the contract including option prices with current appropriations.
On another note... market research may disclosed that a GSA Schedule holder could satisfy the requirement to include other items under its schedule contract. Then it' may be a simple procurement.