Would a temporary increase in earnings mean loss of TP

I have been asked for some advice from a couple and would like to clarify before I give a definitive answer, any help would be appreciated please.

They have migrated from Tax Credits to UC and are receiving £126 per month UC solely due to Transitional Protection.

One of them is a FT carer for her son looking to make a small amount of extra money for a few months, £90 per week for 10 weeks.

I make that out to mean they would lose £198 from UC for the first 2 assessment periods, meaning they would lose UC for those periods.  They would only lose £99 from the 3rd assessment period, then on assessment period 4 would they go back to £126 UC from TP?

I’ve looked at a lot of information online and I’m making myself more confused, if someone could put me straight, we would be grateful, thank you.

They will be OK as long as they are entitled to UC again within three months which they will be by the look of it.  They will “float off” for two months and their transitional protection will survive this short interruption.

See Reg 57: https://www.legislation.gov.uk/uksi/2014/1230/regulation/57