Recharge staff pricing?

[Voadam]

I want to use staves that work similar to the UA variant recharge casting rules.

No charges but each spell requries a different amount of time to recharge before being cast again according to the following chart:

Highest = 5 rounds
2nd highest = 4 rounds
3rd highest = 4 rounds
4th highest = 3 rounds
5th highest = 3 rounds
6th highest = 2 rounds
7th highest = 2 rounds
8th highest = 1 round
9th highest = 1 round
10th+ highest = 0 rounds

How would you price such a type of item?

 

[Pyrex]

For an item that can cast a 9th level spell every 5 rounds all day?

Priceless.

Literally.

As in Artifact.

For a slightly more useful answer:
First thing I'd do is set the recharge time as global for the staff; i.e., you use a 9th level spell in the staff and it can't do anything else for 5 rounds.

Second, I'd base the cost for the top-level power as Command Word 10/day, so SL*CL*3,600gp

For additional spells in the staff I'd use the *.75 and *.50 multipliers for second and consecutive spells as written.