My guild would like to start a DKP decay system with a fixed rate of decay instead of the current variable method.

For example, we would like the system to wait 30 days from the last attended raid and then delete 25DKP per 30 days there after until the player reaches 0DKP.

I'm afraid that's not available, but you COULD do something like that with the mass adjustment option.

Which is what I suggested to my GM, but he'd prefers an automated method.. so perhaps it could be considered as an option in a future update?

While I try to make an effort to accommodate most DKP implementations, unfortunately, I can't support everything someone would suggest.

I plan on implementing more variations to the decay system, ie, linear decay, but with something as simple as a static deduction to DKP, it makes sense to do it with Mass Adjustments.

At best, I can add a "Fill" option to fill in the same number to all players in the Mass Adjustments section.

Probably not that useful for what we're thinking off because we don't want to remove DKP from the entire guild, just those who haven't raided in the last 30days or more.

What about Custom Formulas for Decay like you did for Custom Columns? Now I know it won't work for everything but it might allow people to do somethings they want that you may not consider as long as you provide the needed variable for the system.