You may well be right about the Peace of Amiens period, though I believe there was a good deal of distress among disbanded soldiers, especially officers.
After 1805 was there actually a time when the French army was not occupying foreign territory, if not actually at war? Could France have supported them if they had been brought home and not disbanded?
I think the financial position in later years was not as sound as you suggest, the pay was often in arrears, especially in Spain, and there were large arrears of pay from 1813 still outstanding at the Restoration.
The amounts of money being paid from occupied territories (using the term loosely) to both military and civilians was quite substantial and I understand that both pensions and Legion d'honneur funds were affected by their loss, not just the senior officers. I will look and see if I have any more information.

Susan