Software Deployment

We have saleslogix 6.2.4 in our environment.

The original package needed 2 features, so we took the base msi and created a transform with those options selected.

Now, we need to add another feature in the package.

Here is what I did:
I opened the mst in wise package studio, and selected the new feature to be installed; recompiled the old mst as newtransform.mst. I did not change any product code. I just renamed the old mst, opened it in wise, selected the feature to be installed and re-compiled it.

We use setup.bat to install the product
I am using this command line in the setup.bat:
msiexec /i "filename.msi" TRANSFORMS="newtransform.mst"

Here is what is happening:

On a new machine (without previous install of the product), the install works fine with all the 3 features needed.

On a machine with previous install (with 2 previous features), the new feature does not get installed.
I tried using msiexec /fpecms "filename.msi" transforms="newtransform.mst" (to see if repair will work), but that does not install the new feature.

Is there a specific command line parameter that I should be using to install the new feature on a machine with previous install of the product?

Should I be changing the product code of the new mst?

Thanks