Ofcom wants its cake and to eat it...
Any sane person would understand that as part of the takeover of EE, ALL parts of BT would incur costs as individuals from those departments get involved in working out where service overlaps might occur and hence identify potential costs, savings and benefits, plus how EE might be integrated into the operation.
I find it interesting that the costs in 2014/15 are so low - only £26m, from the noise Ofcom are making you would of thought they were attributing £260m of costs to business connectivity services, rather £1.7m. £0.4m is broadly equivalent to having two consultants working on this full-time for the year.
Rest assured that in 2015/16, the costs associated with the integration of EE's business into BT will be significantly higher.