When your friend reaches State Pension age she will move from ESA to State Pension, I would not have expected any change prior to that happening.
£114.20 is the amount a single person who is in the support group gets as ESA. The difference between the two amounts you give is £17.40 and I can't think of any benefit which gives that amount (although Enhanced Disability gives £17.20).
I think this is a case of ringing the ESA helpline 0800 169 0310 and asking them. They are generally really helpful.
Catherine
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