Allowance on portal wrong?

[#1]

I was just looking at my allowance (500mb to last 1 1/2 weeks, eek!) and I moused over the "warning" indicator which showed the wrong figure.
I have used 12.5Gb out of 20Gb, that is my allowance, yet the figure quoted says 90% (screenshot attached).  I know my maths isn't fantastic but I'm sure than 12.5Gb out of 20Gb isn't 90%, it's umm, let me see if I can work it out in my head, umm, 62.5%?  The one warning (used over 60%) is correct, the mouse over warning is incorrect (unless you changed my allowance to 13Gb total without telling me)

[#2]

Though the allowance numbers could perhaps be better presented the values you are seeing are correct for an unrestricted service. Broadband Premier progressively slows down for usage above 13GB per month as shown on this BB Premier1 legacy product page. This is not a recent change, it's always been like that.

[#3]

Aye, I know at 13/17 it gets throttled a bit (a lot) but it isn't until 20Gb that you're over your "allowance" as it were, after which PN start to block certain forms of traffic peak hours.  On the link provided:

Quote

Broadband Premier Option 1 is provided with 20GB allowance for peak-time (4pm-Midnight) usage.

I mean, I'm throttled anyhow from 4pm-midnight even if I've only downloaded 100k because that's the management platform, it's also on the page linked to, if I go over 13Gb (which I am going to do) my Download Servers will drop to 2Mb on management but in reality will drop to 1Mb because of normal traffic shaping by PN (and even slower for Download Sites).
That's why I believe it is incorrect stating I'm at 90% of my 20Gb allowance, I am at 90% of my 13Gb soft cap which isn't 90% of my allowance if you get what I mean.