The issue is that you're editing the Spare Parameters on the node instead of the parameters on the asset. These are, well, spare parameters. You can add spares on any node if you just need an extra parameter to help with channel references or usability. These spare parameters get saves as part of the .hip scene file and as part of the .otl/.hda.
To add real, permanent, parameters on your asset, right click on your asset node and go to “Type Properties”.
Here's a video that goes over some of this:
https://vimeo.com/158671982 [
vimeo.com]