Hi Jon! If I may where did you find this information? Or is it a calculation of known data?
Clear skies & Good seeing
It's based on an equation someone posted here that was derived from an equation from the book Telescope Optics by Rutten and van Venrooii.
Color blur = (735 x Aperture (mm)) / (Focal Ratio x Longitudinal color error) It's an extension of the Sidgwick and Conrady guidelines. I use an abbe normal chart that was annotated by Roland Christen on astromart. It requires some interpretation but it should be close.
Put in 11000 for the Longitudinal Color error for FPL-53.
Blur = (735 x 100) / (9 x 11000) = 0.74
I use 1900 for achromats, 6700 for FPL-51 class doublets.
If you look at Vlad's work on the Polychromatic Strehl, a 100mm F/9 FPL-53 doublet is almost perfect.