Recently two single-vendor multi-buyer integrated inventory models were developed by incorporating some realistic factors. The production flow was synchronized by transferring the lot with equal-and/or -unequal sized batches (sub-lots), where the equal-sized batches were kept to be equal to the largest unequal-sized batch. A common minimal total cost solution technique to the models was derived, and its potential significances were highlighted with solutions of some numerical problems. Because of the inflexible restriction on the equal-sized batches in the models, they failed to provide the generalized minimal total cost solution to a single-vendor single-buyer numerical problem.