Did UKVI make a mistake calculating C?

[Cambrian]

I recently got a spouse visa rejection. We are a couple with no children. I get carer's allowance so only have to prove adequate maintenance.

The rejection letter contained their calculation of C for the equation A+B>C .


Appendix FM annex 1.7 states
d) Calculate how much a British family unit (of equivalent size to the sponsor and their family
unit) would receive if they were in receipt of Income Support (C).

So it would be reasonable to assume that C in our case would be £114.85 per week. But the calculation they provided I the rejection was as follows:
C=income support for a couple+carer's premium i.e.
C=114.85+34.95=£149.80

Is this normal, they certainly arent using their own guidence as laid out in the annex if so? Or, has someone made a mistake here?

[alphagear]

Apply for carers premium then reapply.

First time i have heard this too.