The formula is for 5-130 and should be extended to cover the rest up to 495. Since the correspondence between the 0-30 range and 5-130 is not linear, this formula is composed of three parts, one for calculating the toeic values for 0-6, another for 7-25 and a third for 26-30.
The formula was tested on Moodle 2. It seems that the syntax of some formula functions has changed from 1.9 to 2 so the formula may not work as is on 1.9 but a small ajustment will fix that. So if you need it for 1.9 and this one doesn't work let me know and I'll post an adjusted version.