SBVR_ — SBVR Issue - Annex C.1.1.3 "only if"

Annex C.1.1.3 includes the following text about "only if"

The key word phrase “only if” is used in combination with some of the key words and phrases shown above to invert a modality.

… may … only if p obligation claim over an implication
it is permitted that q only if p obligation claim over an implication
it is possible that q only if p necessity claim over an implication

The key word “only” can also be used with “may” in an expression before a preposition to invert a modality.

… may … only … obligation claim over an implication

However, there is nothing to explain what is meant by "invert a modality". This section should be extended to define "invert a modality", for example

it is permitted that q only if p (apparently) is equivalent to it is obligatory that p if q

And an example would help.

Without this material, different readers undoubtly will interpret the concept "invert a modality" differently. For example, it would be reasonable to assume this is the same as "negate a modality" and then assume that the text about (for example) "obligation claim over an implication" must be ignored as being inconsistent.

Show modal inversions caused by using the word "only" in terms of equivalences and examples.