MIF for self employed couple with children

I have a client who is carer to 4 children in education between 6 and 19.  She is currently self employed working 16 hours a week and in receipt of CTC, WTC and CB.  Her partner is due to move in later this month and is also self employed working 40 hours a week.  They have had a benefit calculation and been advised they will have a UC entitlement when he moves in, but the minimum income floor of 35 hours a week will be applied to her.  Is this correct or can this be reduced due to her being the main carer of a child under 13 (like it would be for someone in work related activity group?)

The MIF for the main carer of a school-age child is generally based on 25 hours a week. See H4073 here and J2086 here.

Is my reading of CPAG handbook correct i.e.  that MIF applies immediately if you are migrated naturally rather than through managed migration?

Correct, however this will change from September 2020.