possible reason for stalling

I concider anything under the .6/.8 loss a stall. :)

I read Pounds and Inches and feel a bit better:

Page 67: This could be it. Water retention due to fat cells! I HOPE!
The weight registered by the scale is determined by two processes not necessarily synchronized. Under the influence of HCG, fat is being extracted from the cells, in which it is stored in the fatty tissue. When these cells are empty and therefore serve no purpose, the body breaks down the cellular structure and absorbs it, but breaking up of useless cells, connective tissue, blood vessels, etc., may lag behind the process of fat-extraction. When this happens the body appears to replace some of the extracted fat with water which is retained for this purpose. As water is heavier than fat the scales may show no loss of weight, although sufficient fat has actually been consumed to make up for the deficit in the 500-Calorie diet. When then such tissue is finally broken down, the water is liberated and there is a sudden flood of urine and a marked loss of weight. This simple interpretation of what is really an extremely complex mechanism is the one we give those patients who want to know why it is that on certain days they do not lose, though they have committed no dietary error.