YouTube Traffic Shaping under Business Products

[#1]

We're on Business 3 and been having consistent problems watching anything via YouTube in the evenings. Videos stutter to the point that they're completely unwatchable.
Streaming is time sensitive content and needs sufficient bandwidth to be watched without interruption.
I've just noticed that, presently, on the business packages, the YouTube bandwidth ceiling is beneath that required to stream an individual video. The much cheaper consumer targeted packages are far superior in this regard. Is this deliberate or an oversight?
Business Options 1, 2 and 3 get a ceiling of 1Mb/s from YouTube between 7pm to 10pm on both weekdays and weekends.
PlusNet Value and Extra, by contrast, get a ceiling of 2.5Mb/s from YouTube between 7pm to 10pm on both weekdays and weekends.
http://www.plus.net/support/broadband/speed_guide/download_speeds.shtml
We're on the Business 3 package and spend considerably more than we would on a consumer package.
To me, it feels more than unreasonable to have a more restrictive usage profile in this respect.
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Note to any PlusNet staff, I have opened a ticket on this. (# 32970530)

[#2]

I'm on a business product too and have the same issue.
The shaping profile means that, irrespective of PlusNet's network conditions, we're not able to view YouTube videos properly between the hours of 7pm to 10pm.
It's arguable that this makes the products not fit for purpose.