PAYE, Sole Trader and Assessable Spouse

Hi all,

I am looking for a bit of advice and guidance please.

My wife and I are currently joint assessed for tax, I earn over 65k as a paye worker and my wife works 15 hours a week as a paye worker.

She us in the process of setting up as a Sole Trader where she will work part time in addition to retaining her paye job.

When she tries to register on revenue as a Sole trader, she is asked to confirm that she will be the Assessable Spouse for tax purposes. I understand that this means she will have the higher tax credits even though I will earn significantly more than her.

Is this the correct way to go? From looking up Assessable Spouse online I read that this should be the person earning the higher income.

I appreciate any advice, thanks