Thank you for your feedback.
At present we base it on a rolling 12 month period as this matches our costs. Entering 2012's data in 2017 will still mean costs are incurred for us in 2017 for example.
We do take into account imports, which is why we allow all new accounts 60 days free access, regardless of their size. So you can start using QuickFile and have a good look at it's features within these 60 days without any charges.
I don't think this is something that will be reviewed in the near future. At £45 per year, QuickFile is still one of the more affordable platforms.