Self employed on New style JSA

JCP have told client if he registers as self employed his JSA will stop, irrespective of any earnings he may have.

Client may be asked by a company he has applied to, to set up as a PLC before he gets the contract.  JCP have also told him he won’t be affected by the same rules if he claims UC! (which he can’t due to capital/partner’s earnings)

Can’t find anything in ususal sources to support this, JSA only affected if he has any actual earnings. MIF for UC wouldn’t apply immediately anyway

Fact is if he does this and gets contract he will be in well paid work and JSA stop immediately but I am concerned JCP are misadvising him.