iPhone PKGBackup on new device?

I'm trying to restore a new device from a recent backup, and I want to reinstall PKGBackup. I already read the FAQ that says it's possible to use the old license on the new device, but doesn't do a very good job of explaining how! Here's what the FAQ says:

"Q. My device was replaced & I already purchased PkgBackup. Can I still use license on the new device?
R.Yes. Simply install PkgBackup again using the SAME credentials you’ve used when you were purchasing it the first time.
★ ‘Addressbook is your primary storage
Rename the 'Pkg_<LOTS_OF_CHARACTERS> BackUp' entry in your addressbook to:
- First name: Pkg
- Last name: BackUp.
★ ‘Dropbox’ is your primary storage
Login into your Dropbox account using a web browser. Go the directory ‘PKGBackup’ & find the directory that
has your old device UUID then rename it to your new device UUID."

Maybe I'm dumb, but I don't get it. How do I do this so I can use the license from my old phone (which I paid for) thereby allowing Cydia to recognize my new device as the old one?

dhlizard said:

You must also have a backup for the iOS that is on the new device (in other words you cannot use a backup made on iOS6 to reinstall the hacks on an iOS7 device)

Click to expand...

First, thanks. That helps.

Second, wow... seriously?! IMO, that's a big drawback. So you're saying that you can only restore intragenerationally (i.e. 6.1 to 6.1.2), but not intergenerationally (i.e. 6.x to 7.x)? Is that due to (some) packages not being compatible with the new OS?

That's a bummer cuz my old device is 6.1 and the new one is 7.0.4

dhlizard said:

Yep, doing a blanket install cannot be done since it takes developers some time to update their hacks to new firmware - assuming they even do update them, some never do.

Click to expand...

Copy that. So in theory, if I backup only the packages I know to be compatible with the new iOS, it could still work...?

dhlizard said:

We'll, not exactly because some iOS7 compatible packages cannot be installed on iOS6 device therefore you are backing up the wrong version which will crash your new phone.

You know, there is nothing wrong with doing the initial set-up of your Cydia hacks manually on you new phone.

Click to expand...

Yeah, and I think I will. I already did the legwork of noting the important tweaks, so I might as well. Was just trying to save some install time.

Thanks for the help, though.