First off Welcome to the forum!
Second, if I understand you correctly, yes you can and should go from the computer straight to the PV+ using the transfer utility to download your new program.
Note: Not all USB to Serial adapters work with the Rockwell Software. I have been lucky that I haven’t needed to use a USB to Serial convert “yet”.
Also, you should also be able to use the Ethernet port on the PV+ and you Ethernet on your computer for the download and eliminate the converter.
Hope this Helps.