The differences I have found with 'off the shelf' blades and ones supplied by Ian.
Off the shelf are of a specification that are likely to meet the majority of purchasers needs and sourced from a manufacturer who has met some form of wholesale value/quotation selection process.
Those from Ian, if you care to ask for his guidance, are supplied based on his experience and interpretation of what your needs are, and in most instances more than one grade/specification will be offered with the relative merits explained.
If you have a particular problem I can vouch for the fact that he will go out of his way to find a fix to the point of delivering various sample materials and tooth forms to find a product that will give satisfactory performance and life.