I don't care for repeating whole chunks of previous quotes, normally, in view of the repetitive nature and the space consumed, but since this comes from a source far more knowledgable than me, then on this occasion it is essential. This is an extract from a contribution by Frank - in June this year - and can be accessed in full via Anik's link below.
Speaking of variation in mould design, and in egard to the centrepiece in question, Frank (who, incidentally, is somewhere in Europe) says:............."In some cases the variations can be quite dramatic and could even be deliberate adjustments of a design to suit the changing market taste over a long production period. For example Jitka Forejtova 13171 Nude figure http://sklo-union-glass.com/index.php?page=shop.browse&category_id=13&option=com_virtuemart&Itemid=1 311371 shows at least 3 distinct moulds in the examples appraised. As the size of the breasts change that could well be a deliberate change for the market. It would interesting to find a dating for these type of variations but very hard to achieve without dated photographs. But such aspects do make for an interesting study of both manufacturing and marketing aspects with their impact on the design of the SU glass".
Being rather interested in breast size, I rushed to examine my amethyst and olive 'frogs' - but find that I'm disappointed, as on both exampes, these appear to be identical in size (pointy and rather small) - however, by comparing my amethyst nude with the same colour frog in the link, it is apparent that variation 'seems' to have been towards 'rounding' the breast shape. These designs are heavily stylized, so presumably this change was not an attempt to make them look realistic - but it's just possible that angular shapes were considered too 'deco' in style.
However, other mould changes in repect of this 'frog' are also interesting, and again, making comparisons between my two examples, it can be seen that there is an opposite 'tilt' to the angle of the head. Other lines seem to remain in the same direction - but for some reason the head alone has been shifted. Not very helpful looking at just two exampls, but out of interest I did look at weights and dimensions etc. of my two pieces, and it appears that bowls and stands are very similar, but again found variation in the height of the nude................the olive example being taller by about 4mm does have a correspondingly slightly heavier weight of 275 gms., compared with 250 gms. of the amethyst piece. Of course, height variation can be accounted for depending on the extent to which the frog's plinth is ground down - and in the picture you can see how the olive plinth is a little taller.
I don't know whether the price variation (shown in the link) is related to numbers produced, or simply the popularity of certain colours, but there does appear great variation in selling prices.