Why do the metabolism gods punish me when I lose weight?

I have noticed that the fitness gods are mocking me now.  This month I have hit several nice milestones and lost both inches and pounds, but it's coming back to bite me in the butt.  Now, when I work out on the elliptical, the machine tells me that the calories burned are lower.  Noticeably lower.  Even though I took my step count up as an experiment, my calories burned are lower than they used to be. 

In a similar fashion, the number of calories that I need to lose weight are now 1,640 per day - - it used to be 1,900+.  In other words, I can eat less, and I get less credit for my workouts.  Pooh on that.  That is no fun at all. 

I understand exactly why this is happening, and it is all for good reasons.  It only stands to reason that a lighter body requires less fuel every day than a heavier body - - there's less to cart around, after all.  The same principle applies for the calories expended during exercise - - a heavier person burns more calories than a lighter one because a heavier person is carrying more mass and must overcome more resistance than a lighter person. 

But that doesn't make it fun.  I feel like I am working harder than ever, and getting less credit for it.  Boo! I feel ripped off!

On the good side, as I lose weight I am noticing that I get full faster.  Perhaps after 13 months my body is finally adjusting to my new and improved lifestyle.  I don't need as much food now (relatively speaking), and I cannot comfortably eat as much as I used to, so I don't feel as deprived as I would otherwise. 

Tomorrow's big weigh in will be interesting, where I see if I have maintained (or even improved) on my big milestone loss, or whether I have let the weight creep back.  Plus, it's measurement time, being the end of the month and all.  Fingers crossed!