What HTL does is not universally popular, particularly with headphone manufacturers and their PR apparatchiks who would rather you believed their marketing hype – and the outpourings of uninformed 'reviewers' – than subject their products to measurement scrutiny.
If you are minded to resist the march of the uninformed, and own a headphone not listed on HTL already, here's an offer for you. If you send me your headphone for measurement (agreed beforehand, of course), I will test it within two weeks, return the headphone to you with appropriate insurance, and reimburse you for sending it.
If you'd like to explore this prospect, please message me via the Contact page. Thank you!