Traffic (mis)management issue ?

[#1]

I've been noticing some ftp issues for a while and I'm currently seeing repeatable and significantly different performance when comparing webspace http and ftp downloads. It would appear to me that (at least some of) my ftp downloads are being hard capped to around 2Mb/s.  By way of an example, the following graph shows 2 attempts at downloading the very same test file at around 1545 hours on 25th August. The near full speed downloads are http and the quite obviously restricted speed downloads are ftp needless to say. All attempts were performed using Firefox in this instance but I've no reason to believe how the download is performed is in any way relevant because I actually noticed the problem when doing something else using a different application.

Why do PN appear to be somehow throttling or otherwise intentionally restricting a perfectly reasonable and valid activity ?
Answers/excuses/advice/comments/whatever on a postcard please and all that ... because it sure doesn't look like whatever is causing this is at this end of the wires !

[#2]

Which Plusnet package are you on? Some of the previous packages did have rate limits for certain types of traffic at certain times, which were stated on the broadband speed / traffic management support webpages. FTP has always been given a fairly low prioritisation, one of the legacy packages gave FTP rate limits that were almost as low as those for P2P and binary usenet.

[#3]

ejs has hit the proverbial nail on the head.
Your on a very old package which limits FTP after 4pm.