If you modify an admin form, lets say you add a column to the database for another field. If you start to test, but the form is not saving the new fields, and it appears that Magneto is ignoring your new columns, well....it is.
Long story short, there is a function called
protected function _prepareDataForTable(Varien_Object $object, $table)
Found In :
This runs through the table to get the columns.
The problem is that some of that information is stored in a cache/memory. So even if you may have your caches disabled in Magento the way to fix it is to flush the Magento caches.
Hopefully this saves someone several hours of headaches.