I do not understand either, we gave you the best examples.
If any item just only has light property on it, I not going to pay more then 32k for it on any server/module. So making the light property 0 seem reasonable. Other properties on it will still adjust the price.
You could do like The Amethyst Dragon said and just make it temporary, but for a long time.
And like Shadooow said if you using his patch it auto adjust the spell.
or if you have my base you can use quality property where I put in wide set of price adjuster you could add.