Plugfest, text-line-through-type and style

From the tests performed on the The Hague plugtest wiki.

ODF 1.1 contains two attributes to specify if and how a text can be striked through: 15.4.6 Line-Through Type and 15.4.7 Line-Through Style
(+ 15.4.28 Underlining Type and 15.4.29 Underlining Style)

However, it is not clear what should be done when one of these attributes is set to none and the other isn't (which one has precedence ?), and what happens when one of them is omitted (default "none" ?)

ODF 1.2cd2 18.364 style:text-line-through-type even has an editorial note on this duality

"Tricky. If its value is none and style:text-line-through-style is not none, then a single character can be used for line through. Otherwise, if it has the value single or double, then line through occurs. So, the only way to avoid line through is to have "" (empty string) or avoid this attribute altogether? Seems like a very difficult way to accomplish this goal. "