Base on you LRC above, unless the soft start has a bypass contactor ( I don't mean the isolation contactor that's switched on after the motor has reached FS) I think the 644.3% you have is high. For NEMA code F max. LRC would be 560% FLA...
In addition to krisys earlier comments, please refer to the following articles/standard:
NEC 110.16 and OSHA 29.CFR 1910 Subpart S. I think those should answer your question.
