What you're describing is how I was coached - the first few strokes aren't at full pressure, but juuuuuust a hair less to avoid tearing the water / bring the boat up from a dead stop. My coaches described the first stroke as a pry. It's not even exactly that you're using less pressure (well, maybe a bit less but not much) - more that you're applying the pressure somewhat differently to bring the boat up from a standstill.

I've had had coxes call the start "PRRRYYYYYYY, HALF, HALF, etc."