What's the significance of the H818 on the original Tamla release label and the H909 on the Tamla reissue label?

It appears that the H818 version runs 2:20 while the H909 runs 2:30 - 

 

H818 has the incorrect running time. H909 has the correct running time of 2:30. If there's an actual difference in the mastering, I can't hear it. 

Thanks guys. Where did you find this out? What's your source?

PS - Have you tried locating a reissue copy of this record with 'square' Tamla design? They seem very hard to come by?

3 hours ago, Denbo said:

Thanks guys. Where did you find this out? What's your source?

I listened to both copies/versions and timed them. 

4 hours ago, Nick Soule said:

I listened to both copies/versions and timed them. 

Yeah but what made you think the H number had anything to do with the timing of the record?

4 hours ago, Denbo said:

Yeah but what made you think the H number had anything to do with the timing of the record?

It was the only other visual difference between the two labels.

H### is a master number numbering sequence that Motown used for a brief time starting in 1961, I think. H909 is a later master, and you would assume there would be audible differences, but I don't hear any. And according to both Reginald Bartlette's book and the Don't Forget The Motor City site, both masters/versions were released at the same time.