Is it normal to be FLATTER after an explant than before the implant?

Thank you for the question. Generally speaking, what  breasts will look like after explantation depends on several factors such as: the quality of skin elasticity (the better the elasticity the better the skin will bounce back), the size of the implants used (the larger the implant the more trouble you may have with redundant skin), and the amount of breast tissue present at this time (which may have changed since the time of your breast augmentation).
Life experience since your breast augmentation procedure, such as pregnancy or weight gain weight loss, will potentially influence the factors discussed above. If you take these factors into consideration and apply them to your specific circumstances you may get a good idea of what to expect after the implants are removed.
Patience is definitely indicated after removal of breast implants; it will take many months for the skin to “bounce back” and for you to see the final appearance of the breasts.  In the meantime, I would suggest that you continue to follow-up with your plastic surgeon on a frequent basis;  he/she will be in the best position to rule out and treat complications and will be in the best position to provide you with meaningful reassurance.
I hope this, and the attached link, helps.

Since you started out with very little tissue to begin with, and then were stretchedout with implants, it is fairly predictable that unless you gained weight in your chest and the breasts grew that you would end up being flat with the removal.