Mirror refiguring, cost effective?

There is a new Sponser, SciTech, that does refiguring. They guanatee some mighty impressive numbers!
This is one of the mirrors they have for sale.
(8" f/7.5 Parabolic Mirror 1/33.4 P-V, Strehl ratio .998
Pyrex Substrate, 1.375" thick)
The refiguring is guanteed to be
"Re-Figure Specification:
We will re-figure your mirror to a minimum specification of the following:
Strehl Ratio of .960 or higher
RMS Surface error of 8.4nm or better
P-V Surface Error of 1/18 wave or better"

My question would be this.
Would it be worthwhile to spend $314 ,including coating, to refigure a 12.5" mirror that was 1/10 wave of better by Discovery?
Would you gain enough to make the cost worth while?
I am wondering about this as I could use a recoating on this mirror as it has spots of something on it like over spray that will not come off with anything. Doesn't seem to hurt the images, but it would be nice if they were not there. I have thought about a better figure and coating a lot, but can not decide wether it would really be that visually improved when it was finished.
What do you guys think?
Floyd

That seems a good price for what is advertised.
Comment: Make sure you have a good substrate.
I once paid big $ for a refigure just to discover
the glass was never annealed properly -- after a
super accurate refigure, it warped during
re-coating!

I wish somebody can refigure my atomsphere, which is normally worse than 1/2 wavelength and maybe 2wavelength tonight

Clear and Steady Skies,
GY
http://planets.lamost.org/

Floyd, if your Discovery mirror is 1/10 wave *P-V*, which would be 1/5 at the wavefront, then it may be worth the money. But if it is 1/10 wave *at the wavefront*, then there's no point in having it refigured. But even at 1/5 wave wavefront error, atmospheric seeing will probably be your limiting factor nine nights out of ten. How do you "know" that the mirror as it stands is indeed is 1/10 wave, and is it P-V or at the wavefront?

Are there any noticeable defects in the diffraction pattern that you can positively attribute to the primary mirror? If not, then I would do some more evaluation (like have the primary independently tested, or do it yourself) before spending that much money. But if refiguring is warranted, then it sounds like a bargain, if they can achieve what they claim.

All IMO anyway.

Best regards,
Doug Scobel

Floyd
Read my post. Have Steve Swayze test it, he is one honest down-to-earth guy who will not try to simply sell an unnesseccary refiguring to you.
Joe