Sorry for the delay. Yes, you have enough maps processed to be able to upload more data but you have a Free subscription and 155 points in your account so you are limited by that. You get your one free gigapixels worth of imagery and the 155 points is enough to process another .75ish gigapixels. That is going to be roughly 145 12 megapixel images. Then the uploader lets you select up to 4X that to allow you to choose .25 downscaling.
It should tell you how many images you are allowed to upload in the line marked here:

This shows you exactly how many images you can select given your plan and points.
If you want to process larger maps you would need to either up your subscription access tier or purchase pay-as-you-go points.