TOY: optima yellow top change???

[David Knight <knight@xxxxxxxxxxxxxxxx>]

Hi,
    Two years ago I purchased an Optima yellow top
battery. Model D750U, part#8014-021, 65 AH 750 CCA.
I liked it so much I just recently purchased another
Optima yellow top (thinking it was the same battery).
This new yellow top is part#D34/78-950, model#8014-045,
but has only 55AH and 550 CCA. It looks like the
same battery, but the capacities are notably smaller.

Anybody know what is going on here?
Thanks
David