Yes - using custom parameters with Nevron JScipt are usually performing better than connected webparts, since the latter perform a complete postback to force the page to go through the web parts connection phase (page pre-render).
The client side will initiate a InitXXXParam POST request, after a certain delay, any time you call the respective NInitXXXParam method. The delay is needed for a multiple params on the page to be grouped in a single Init Request to the server, so the initial POST that you get is perhaps from a global script block, that gets executed when you load the page.
Can you please elaborate on the client side scipt that you use to Init/Set Nevron parameters and to respectively refresh the Nevron webparts. Please note that Nevron parameters are by default initialized to REFRESH ALL Nevron WebParts when any paramter changes. However you can init parameters do not refresh the webparts - to force a refresh of the webparts that use this parameters you can call the NRefreshWebPart method.
See this topic in the help:
Nevron Support Team