You're correct on wasting a month of LCA - 回复:各位大狭:有关H1B,LCA-I12
You're correct on wasting a month of LCA, but not losing a month of H-1b.
It is a practical strategy to apply LCA ahead so as to file I-129 on 4/1 if you're cap subject, though it is believed that the quota would not be exhausted as quickly as past years.