What difference would it make in a fire? If the compartmentation & smoke control is fine, travel distances are fine, the most common risks are in a flat, normally only a single flat is initially involved, etc how would the few extra flats per floor affect life safety? Bearing in mind as well it's moderate height.
Possibly not much, which is I'm guessing how it got passed in the first place, Does it justify the expense of installing a full evacuate system and the ongoing access, maintenance and leaseholder cost burden associated with it, is the benefit worth it? What is the occupier mix - would the change potentially lead to a need for multiple PEEPs having to be implemented simultaneously as oppose to one initially if stay put (that's an assumption on the way the proposed block RP evacuation responsibilities may end up going) .
Does the layout support remediation to nearer the benchmark with lobbying with a partition wall & fire door? Is this proportionate?
I've not seen the place so I can't say either way - but these are things to consider