Teaching An Old Magic Item New Tricks

Last night there was some short discussion about whether you can add new enchantments onto an existing magical item. The RAW allow you to do this. Here is the passage from the Core Rulebook:

Sometimes, lack of funds or time make it impossible for a magic item crafter to create the desired item from scratch. Fortunately, it is possible to enhance or build upon an existing magic item. Only time, gold, and the various prerequisites required of the new ability to be added to the magic item restrict the type of additional powers one can place.
The cost to add additional abilities to an item is the same as if the item was not magical, less the value of the original item. Thus, a +1 longsword can be made into a +2 vorpal longsword, with the cost to create it being equal to that of a +2 vorpal sword minus the cost of a +1 longsword.
If the item is one that occupies a specific place on a character’s body, the cost of adding any additional ability to that item increases by 50%. For example, if a character adds the power to confer invisibility to her ring of protection +2, the cost of adding this ability is the same as for creating a ring of invisibility multiplied by 1.5.

So unless we decide to house rule this my future rich self plans on lighting everyone’s ass on fire by myself the next time you’re hostile, greased and glittered and not with the help of some untrustworthy gnome.