Replacing Linodes

I have two Linodes and they are pre-paid for quite some time. They are running very old software. Instead of updating them in-place I want to make two new nodes, re-point DNS records, and then turn off the old ones. That's a pretty standard practice to make smooth upgrades to new systems without downtime.

I was just curious how this much would cost. I think I found the answer in the documentation, I just want to confirm this is 100% correct, so I don't end up accidentally spending a bunch of money.

> If you remove services from your account, you will be issued a prorated service credit for the time left in the current billing period. This credit may be used to purchase additional Linode services in the future. Service credit is always used before charging the credit card on file for ongoing service.

So if I buy two Linodes, temporarily having four in total, the only additional charge will be for the short period of time the two extra nodes are up. Once I turn the old nodes off, the price I paid for them will be credited to the account and will pay for the continued existence of the new nodes as if they were the original ones. Is this correct?