FYI: Most "methylation" tests, books, and treatments are very firmly in the alternative medicine category. Much of it is pseudoscience.
It is true that a small subset of people can have a certain set of mutations that has clinical significance, but the alternative medicine community has been hard at work trying to expand this condition to cover far more people than it actually does.
One common trick is to perform as many tests as possible, along with as many permutations of those tests (e.g. the various ratios between values). The more tests you conduct, the easier it is to find one that might be out of a specific range and therefore convince the purchaser that the test was worthwhile. If you really wanted to test something, you'd skip this test and get a cheap genetic test to see your MTHFR variant (note: heterozygous is fine, no matter what the naturopaths try to tell you).
It's also common to claim a test has significance in every medical condition that people might be Googling. The test you linked is guilty of this, claiming to be "Useful for" everything from autism to birth defects to cancer, down syndrome, immune dysfunction, nutritional deficiencies, psychiatric disorders and more.
Any test that claims to be relevant to so many different medical conditions is a huge red flag.
Save your money. If you're curious, you can read more about how the whole "methylation" and MTHFR alternative medicine got so out of control because one naturopathic author pushed it so hard as an explanation for everything: https://www.mcgill.ca/oss/article/pseudoscience-reviews/gene...
There's another good article here about why this test isn't really warranted for most people: https://health.clevelandclinic.org/a-genetic-test-you-dont-n...