The companies are already gearing up for this change.
Rumor has it, in addition to the 500 hours TT, you will only get a validation of your licence until you have 500 hours flying IN Botswana before you can have your licence converted. Assuming this is why you already having to have the types on your licence. (Note conversion VS validation) That is coming from the Chief Pilot of one of the companies.
The government have been trying different things for many years now. This will probably fall away. They always make a huge noise for a few months then realize it's not really sustainable (or too much effort to keep fighting the companies). They have yet to get it right so let's see how long this attempt lasts.