I was given such a print out on my first in person 90 day report. I then reported online on said such date and was refused! So yes, it is confusing as the immigration want you to report 1-2 weeks before the date you are given!
You have a choice of NON O visa or NON OA visa. For the NON OA visa you will need 800,000 baht in your bank plus health insurance. NON OA visa gives you one year plus an extra year when you do a border bounce just before the first year expires. All you need to do when you arrive in Thailand is a TM30 which states your address in Hua Hin then do a TM47 report every 90 days.
A NON O visa does not require health insurance, you get 90 days then you apply to extend.
You can apply on the Royal Thai Embassy London website.