From what your literature states, that model is compatible with ANSI M59 CWA ballast used for 400W MH. A 400W MH high bay with a 400W MH uses around 450W. When the lamp is replaced with said 330W Philips lamp, what is the expected input power? What kind of power factor can you expect?
I haven't looked into ANSI codes, but the could the said lamp be used with HX-HPF ballast meant for 400W MH and if so, what happens with power factor correction as the capacitor is sized for 400W lamp in mind?
Hope this helps. Meanwhile I have to find out for you what the actual power consumption / power loss is of the ballast when using with our retrofit lamp...I would assume it's the same as with the original lamp.