How many disconnects to cause reduction in IP Profile?

[#1]

Please would somebody point me to a statement that defines how many disconnections or breaks of what duration over what period will trigger a drop in IP Profile?
I ask this as recent diagnostic tests for low speed seemed to cause the IP Profile to drop from 750 to 250 Kbps  and I don't want to accidentally cause that to happen again when the replacement router arrives. Also, I probably need to get BT to check the line for voice quality and I'm sure they'll want the router unplugged.
Is there a safe period - e.g. an hour - between disconnections that will definitely not cause IP Profile reduction?
Thanks.
John

[#2]

I don't think anyone knows the answer to this question hence:

How many disconnects does it take
To cause an IP Profile to fall?
And how come my download speeds are so bad
When my sync rate ain't bad at all?
What happened to the promise of "super-fast"
Now my broadband has slowed to a crawl?
The answer my friend, is blowin' in the wind.
The answer is blowin' in the wind.

(with acknowledgements to Bob Dylan)

[#3]

Nice one!  I'll get my harmonica. . . . 
But, seriously, is there not at least some folk-lore answer that gives a safe interval for tests that need disconnections?
John

[#4]

The answer is that you log on to the router and ask it to disconnect, rather than just switching it off or pulling the plug.  The reasoning is that the equipment in the telephone exchange (DLM) will see this as a "planned" disconnection instead of an accidental outage, so it won't count against you. 

[#5]

[abbr=How many disconnects does it take
To cause an IP Profile to fall?
And how come my download speeds are so bad
When my sync rate ain't bad at all?
What happened to the promise of "super-fast"
Now my broadband has slowed to a crawl?
The answer my friend, is blowin' in the wind.
The answer is blowin' in the wind.]How many disconnects?[/abbr]
Brilliant!

[#6]

Thanks RR. I was worried that, even though the "Internet" light goes out after I use the disconnect via router control web page, the "Broadband" light stays on. That made me think that perhaps the exchange doesn't see/care about the end-to-end connection and would still see subsequent power off as a break. 
Anyway, with the downlink crawling at 240 kbps, even though the sync is > 1 Mbps, I'm not likely to make things much worse!
Wish I could get that tune out of my head now!!!
John

[#7]

Hi antenna,
I've just matched your BT & PN profiles to 750k so you should notice the difference if you disconnect and reconnect via the router homepage.
Jojo

[#8]

P.S. I can't get it out of my head either!