Does anybody using this forum understand the precise rules behind the fare restriction "END-ON-END NOT PERMITTED" ?
I'm in Kuala Lumpur now, flew here on a round-trip KLM flight from AMS .
I'd like to go to Jakarta for a couple of days before heading back to AMS. I see that KLM have staggeringly-cheap fares KUL-JKT $68 round-trip all-in.
I was poised to book one of them today but I read in the fare rules (in the AMS-KUL ticket that I'm part way through using and also the KUL-JKT cheap tickets ) that END-ON-END NOT PERMITTED.
I understand the basic concept behind that restriction but is there a time element involved ?
For example; if I were to fly to a ciity and then 5 months later ( before heading back home ) took another KLM flight. Would I be in breach of the fare rules.
I can find no exact explanation of this anywhere.

Please could somebody provide a definitive answer?