Did I get this right?

[mbyron]

Working a scrimmage yesterday, and I'm a rookie FB official.

I'm on the wing, and the receiver on my side jumps forward before the snap, but not into the neutral zone. I threw the flag and whistled it dead for false start.

It occurred to me afterward that this could have been IM, motion toward the line. But I reasoned that, since he had jumped, not merely stepped or rocked toward the line, he had made a motion simulating the snap and so false start was the right call.

Is that right? TIA.