An off-set dish is actually an angled slice through a prime focus dish, if you look at the dish from the LNB's point of view it looks (more or less!) circular at that angle. Because of this you can't use the same profile all the way round as VS did with his petal extensions. Also, because of that, conversion between PF and O/S is thus not possible.
When you add extensions to a dish you're not altering the focal point of the dish, that's why the LNB needs to stay in the ame position. What you DO need to alter is how wide an angle the LNB will accept the signals reflected from the dish. This is the ratio of the diameter of the dish (which will increase) against the focal point (which stays the same). This is why you need adjustable scalar rings on the LNB horn. If you don't have this adjustment available then the LNB will simply ignore the extra signal coming in - or at least it will if the original horn was properly designed and adjusted.
Finally, VS is using his dish on C band which uses much lower frequencies than Ku band. This is important because the higher frequencies of Ku band needs an accurately shaped dish profile. Your profile indicates that you're only on Ku band.
