After finding nothing via searches here, and more out of curiosity than necessity, I've observed the following, using MS Excel 2010 on WIN7 PC.
A Number-formatted alpha-space-numeric cell-entry such as
(no equals or plus sign; but with a space)
becomes, on hitting Return:
But there is no similar conversion for some other alpha-space-numeric combinations such as:
So there doesn't appear to be a general conversion process involved.
On the other hand, if the cell was formatted General, it converts
4 P to “4.00 PM” and automatically changes the cell format to Custom.
I can see the sense in this, but can find no indication of why or how it would convert “4 P” or "1 A", but not some other alpha-space-numeric combinations to a number.
Assuming this occurs on other people's machines, can anyone explain what's going on here, please?