War Heroes #5 and the missing four issues

The question which has stumped me for a long time re: War Heroes #5 is this: Are there 4 other issues of the War Heroes series?

War Heroes #5 was published late in 1980. The copy on AusReprints has a 3 written on the front cover which suggests an on-sale date c.December 1980. However, James' data from the Mitchell Library - stamped 30 October 1980 indicates it was on the stands in September/October 1980.

There are 4 other War Heroes issues published by Murray that I am aware of, and given they share a masthead as well as a title, they are clearly related in the eyes of Murray. They are:

War Heroes Planet Series 1 #4 c.January 1978

War Heroes Planet Series 2 #2 c.June 1979

War Heroes Planet Series 3 #4 c.April 1980

War Heroes NN c.February 1981

Now, admittedly, some of the dates above are a little rubbery - a couple may be out by a month or three - but they are serviceable as a guide for my immediate purpose.

Given there are 4 other War Heroes issues, it is tempting to deem War Heroes #5 as the fifth issue in a loose series as per above. If this is the case, then War Heroes #5 was published after War Heroes NN, which seems unlikely. 

War Heroes NN is a larger format magazine size edition, and is similar to many other magazine size one-off issues which have a connection to other Planet Series titles. Indeed, these one-off issues form a proxy Planet Series 4 (one day I'll collate them in a Planet Series 4 gallery...). My dating of War Heroes NN to c.February 1980 is not precise. It is a guesstimate based on Planet Series 3 ending c.November 1980 and the $0.90 cover price issues ending c.April 1981. Future data may amend this date.

So War Heroes #5 was published at the tail end of Planet Series 3, and likely shortly before War Heroes NN. If 4 other issues preceded War Heroes #5, some may have appeared on the stands around the same time as Planet Series 3 #4, or shortly afterwards. This is possible, but doesn't seem likely. I don't see this pattern reflected in other Planet Series titles.

For the moment I'm left with the conclusion that War Heroes #5 was misnumbered. Maybe it should have been #1. Maybe it was intended as a genuine Planet Series 4 issue. 

Or, maybe there are 4 other issues in the series and I just haven't seen any in the last 20 years. TBA.