From what I've read there were two prototypes of the Type 4 built and one for the Type 5. The two Type 4s seem to have been completed, the Type 5 was found incomplete including not having the main gun mounted. Neither was put into production or saw any service.
The Japanese did produce about 200-250 of the Type 3 Chi Nu model with the Type 4 turret and 75mm gun mounted to the hull of a Type 97 Chi Ha. All were kept in the home islands for the Allied invasion and so never saw service either.
Steve: Good eye, all of these were based off the Type 97 Chi Ha but beefed up- on steroids if you will.
BTW: Chi is a prefix meaning Medium Tank. Ha, Nu, To are numbers- aka Chi To - Medium tank type 4...