It sounds like OfCom's actual intent is to use charges as a stick to try and make ISPs lean on Openreach do better at attending appointments - which is fine in principal, although it's probably more effective to just lean on Openreach directly.
But it fails because all it will do is drive your your ISP will to hedge their risk. Effectively you'll get compulsory insurance against faults bundled into your bill - say an extra £5 on install costs and £1 on your monthly bill - so that if the ISP has to pay out then it comes from the extra that everyone has paid already.
At the end of the day, the payout money has to come from somewhere, it can't be miracled into existence. And all the money that flows into a business comes from it's customers, so by definition any payouts will come from the customers.
It's all smoke and mirrors, pay no attention to the increase in your bill, focus on the big payout, don't stop and realise that nothing has actually changed and nothing is better because here's a "free" month that you paid for in the preceeding year.