fortuntately the ATO don't differentiate between endorsement types. Sounds silly but it is all self education provided it 'value adds' to your cadre of skills. If I was in IT for example and worked on IBM products in my current employment and I decided to go a and 'self educate' and pay (like that would ever happen in any other industry!) for an apple course then that would be a legitimate expense because I was expanding my skill base even though in my current position I was not required to use apple products.
Another example is doing a post grad uni course, you might be doing an MBA but you are not currently administering a business, you might be the copy boy but it is your chosen field and you are working in the industry.
The ATO obviously does not like large deductions such as the 30k for endorsements but they have avoided court cases debating it because they know they are f@cked when it comes to self education.