Found it! The reference to the 750 units is found in Doc 92, page 4, para 18. Apparently digEcor never paid for them.

18. The Purchase Order speaks for itself. e.Digital alleges digEcor has neither “released for production” the 750 units, specified “another contract manufacturer” for such units, reached agreement on delivery dates for those units as contemplated by the Purchase Order and the DRM, nor completed the 1250 unit order (a condition to the 750 unit order under DRM paragraph 6) so that there is no binding agreement or obligation between the parties regarding the 750 units. e.Digital denies any remaining or inconsistent allegations in paragraph 18 of the Complaint.