Swapping benefits and then potential impact of Universal Credit

Current circumstances

Wife
Wife DLA award for last 2 years (sight) increased following stroke
Daughter lives with them-20/01/93 not doing anything at present
(daughter not treated as non dependant due to DLA)
Private rented 3 bed house pay 160pw
Pay council tax of around 10pw

Benefits currently in payment

Wife: Husband
IR ESA CARERS ALLOWANCE
Personal Allowance (couple)
Support Group Element
Enhanced Disability Premium
Carers Premium)
DLA HR MOB and HR CARE until Aug 14

HB and Council Tax Reduction

If they were to swap benefits

Wife: Husband:
DLA HR MOB +HR CC CARERS ALLOWANCE
Credits only ESA claim / IS as carer-
Support Grp- underlying entitlement Personal Allowance (Couple)
Disability Premium
Enhanced Disability Premium
Carers Premium
HB and Council Tax Reduction

From my figures if the Husband claimed as main claimant (carer) they would get a little more each week (around £9-10). This is because although they lose the Support Group element they gain the Disability Premium which is nearly £10 more. (The Disability Premium does not apply to IR ESA)

1) Can anyone see any issues / pitfalls with swapping benefits?

If this works we are wondering about the possible impact Universal Credit will have.
Our calculations show that there is no difference in amount for both scenarios when the estimate UC box is ticked in lisson grove-providing the Wife has ‘main phase (support grp) limited capability for work LCWRA’ which she does at the minute.

2) Can anyone see any issues with swapping when universal credit comes in?

Thanks for you help and time with this

Ian