Cow and Gate making it more difficult?

The manufacturers of baby milk tend to get a tough time. See, for example. George Monbiot or anything by the pressure group Baby Milk Action.

The criticisms may or may not be fair. However, if the average UK consumer is like me, you know that baby milk is not as good as breast milk but also that there is no alternative and you want it to be as good as possible. Therefore, you want to know that the company is acting as responsibly as possible.

I was surprised, therefore, when I purchased my second carton of Cow and Gate 1 for my baby. The instructions explained that each packet needs to be started from scratch - that you can't take powder from a previous packet and mix it with powder from a new packet. Apparently, they innovate so often that the powders may be different.

I'm delighted that Cow and Gate decides to innovate. And surprised that when a new innovation is introduced, it isn't advertised on the packet. I'm even more surprised that the balance of chemicals contained in the powder is so vulnerable that mixing two different versions may be unhealthy. (I'm discounting the possibility that a five month old baby who has only previously drunk milk has a highly developed palate.

The cynic in me would suggest an alternative hypothesis: that:
a) Cow and Gate know that the average packet contains a volume of powder that ensures that the average customer will always be left with two or more scoops (I had four) at the end of a packet.
b) Consumers intuitively mix and match with old and new packets (as you would with, say, chopped tomatos)
c) consumers would rather protect their baby's health than lose a few pence
d) by urging us not to mix powders 'because of the innovation' they can make 20-30p extra per packet

Because if I'm wrong - and it is because the mixture of ingredients is so volatile that it shouldn't be mixed - the FSA should investigate immediately.