I wonder if the £145 is what she is entitled to from the State, made up of pension plus pension credit. The balance of £23 could come from a small personal pension or notional interest from savings.
Remember there is the guarantee part of pension credit as well, so even if your income is just above the £167, you can still get extra money. I think the outside weekly income limit for Guarantee Credit is £190 if you are single and £300 if you are a couple.
The simplest thing is to put in an application. The letter granting PC, or not, will contain all the calculations about how they have reached the decision and how much is due, if appropriate.
If you have a small pension, just apply for PC anyway, the worst they can do is tell you you are not entitled to it and remember, as well as getting free tv licences if you are on Pension Credit you can also get a Council tax Benefit, and if you rent, Housing Benefit as well.