Dating Murray's All Star Heroes and The Phantom Zone one-shots

Murray Comics' All Star Heroes one-shot was published 25 August 1982:

I have spotted no less than seven copies to date with a newsagency marking of 12 either on the front or rear cover. Given the rule of thumb for these dates has been a three month lead time, I would usually have no hesitation in deeming it a September 1982 release. This issue also has the Hubba Bubba Gumfighter Comes to Town [2] [Four Great Flavours] ad on the rear cover which, by my reckoning, places it within the August-November 1982 period, therefore providing some corroborative evidence.

However, as a $0.95 cover-priced issue, September 1982 is just outside the range of my dating schema for the 100-page Murray/Federal issues. That is, the $0.95 cover-priced issues end in August 1982 and the $0.99 cover-priced issues begin September 1982. Of course there are always allowances made for some crossover or bleeding between these months. So it was gratifying to spot a copy of All Star Heroes with a firm date on the cover: 25/8. 

This issue includes an ad for The Phantom Zone one-shot, which is advertised as out next month:

Note the cover on this ad has a $0.95 cover price. By the time it was released it was priced at $0.99:

Having dated All Star Heroes August 1982, it would be logical to date The Phantom Zone to September 1982, a month after All Star Heroes. Supporting evidence for this date comes from Hubba Bubba [2] ad in this issue.

This issue also has the Do You Like To Draw? contest which closes 30 November 1982:

I have spotted two copies with 12 written on the cover, and one copy with 1 written on the cover, again placing this issue between September-October 1982.

It's clear the late August publication of All Star Heroes was close enough to September for many newsagents to give it the full three month plus shelf life to December. The late price change to The Phantom Zone suggests there was some delay, which might have pushed it to a late September or even an October publication date.

So on balance I deem The Phantom Zone to be published September 1982, but I would love to see a copy with a firm date on it.