Addon Settings, Can I Add Entries?

I have added some configuration data for products to a separate table.

I can import/export, and select the data from the table in product admin, and view it with the product.

works great, very little code to handle it all.

today I needed to add another element to the extra data, with a few entries in the new table…

But I had to get all the way to mysql to do it… not very admin friendly…

I'm not sure how many times we would ever need to do this in practice, but I'd love to do this from my addon settings menu… but I don't find a mechanism to 'add' things.

I can select from a fixed list, but can't add entries to the list…

did I misunderstand the capabilities here?

our data is really like product data settings.