not sure I can help you with your specifics but the T&Cs on the BMI website are very misleading.
At least when I booked last week, when you click on the fare rule links (eg wowbmi or tinyn) the Ts and Cs are completely differnet to those you see when you click on the links on your e-mail confirmation.
You then cancel your fare and don't automatically get a full refund even though you cancelled in less than 24hrs (although the kind lady at refunds is now sorting that for me)
Finally, I'm getting really pi$$ed off with the likes of BMI and Ryanair (and all the others for that matter) advertising fares without including costs (in order of importance) such as, fuel surcharge, mandatory card fees, mandatory offline fees, mandatory 'booking' fees per sector, tax, charges etc etc.
It's about time the ASA (or the government) got off their backsides and mandated you can only advertise in big letters the full cost of the journey (including usual extras such as credit card surcharges, offline booking fees)
Yes, allow discounts if booked online (within certain limits to stop Ryanair offering 60% discounts to get around it) and maybe others such as credit card discounts (max %age?) but they should only be allowed to LEAD with the USUAL lowest price most of their customers will actually HAVE to pay.
rant over