Can you sell off attributes while in alternate form?

So in BESM 3E, under alternate form, it states that you are allowed to ‘sell off’ attributes to get back character points. Are you allowed to sell back the alternate form attribute for a net of 19 points while in your alt form? A couple people in my playgroup have done it this way and to me it doesn’t feel that you should be allowed to sell off the alt form attribute.