Given the variation in JOC course content also be aware that some operators will specifically ask for a JOC that contains XX amount of hours. So not all JOC courses are acceptable to all operators. I am reasonably certain that Jet2 require a JOC that had at least 16 hours in the syllabus, where as Wizzair would accept any JOC.
Still quite alarmed that Wizzair expected me to have a JOC to apply even though I had two heavy turboprop ratings on my licence.