BB Plus or BBYW 2

[#1]

I am currently on Broadband Plus, but thinking of migrating to BBYW Option 2. I have never gone over 5 Gb in a month in total, and rarely approach even 3 Gb in prime time.
I don't use P2P or Usenet, and I don't understand the difference between 'Download sites' and 'Download servers'. However I notice that between 18:00 and midnight, the speed for download sites would drop from 512 to 256.
So apart from the increase in useage allowance which I am unlikely to use, I can't see much advantage in changing. Or am I missing something?

[#2]

It would give you more flexibility should you have a busy month, or should your usage habits increase over time (as is the norm).

[#3]

Thanks James (that was quick!).
I am a senior citizen, and am able to make the most of the BB+ free useage until 16:00 daily. So even if I did have a busy month, it would most likely be during the free time.
Looks like there is no compelling reason to change ......... yet.