Software Deployment

Hi,

I didn't know where to put this post, but I'm clutching at straws already.

I am creating patches between two MSIs using MsiMsp.exe.
This is obviously done using a PCP file.

The question I have is as follows:
Can I use the same (untouched) PCP file for two consecutive patches?

I've noticed that when I do this, the first patch installs updates perfectly.
The 2nd patch created using the same untouched PCP file seems to ignore all the files and updates nothing.

There are no errors thrown in the process.

The next question is:

If I create MSI v1.0 and install, then create MSI v1.1 and apply the patch (this updates the installation to v1.1 of the application).
For the patch to upgrade to v1.2 - I use the v1.2 MSI as the upgrade, but do I use the v1.0 MSI as the target or do I use the v1.1 MSI as the target?
I assumed that I would use the version of the MSI that matches the installation on the machine. In the above case, MSI v1.1 would be the target - is this right?