I am not sure if it is Youtubes policy that you can not use multiple accounts? If so then yes, you will need to log in via a different IP address every time.
I have administrated high traffic websites that use such tools to catch multi account holders and a flag would be raised for the mods of Youtube to easily see (if they have such policy). A flag would also be raised if you had a different IP address every time you signed into a single account, as in, each IP address belongs to an entirely different country (as non-static IP addresses are issued from ISP's, but never hailing from different countries).