Always have changed per hour and per customer. MAN-ALC tomorrow was £140ish last night but now £175 on same phone but only £160 on second phone yet Harrold was quoted £188. From experience, if lots of seats available price will drop tonight.
Have booked many low cost flights at last minute at much lower price than amount quoted a couple of weeks earlier but most dont want to take the risk of selling out and probably not from MME where there is less competition.
Same goes for hotels and car hire deals.