If your Google Postmaster account shows more domains that you can see in the GlockApps Postmaster Tool, this means that Google API returnes a restricted number of domains for the currently authenticated user (the account you connected to in GlockApps Postmaster).
You can verify the settings for the current user in Google Postmaster and ensure the user has been granted access to all required domains in the Google Postmaster Tools. Otherwise, domains that belong to another Google account or are not explicitly shared with the current user will not be visible in GlockApps Postmaster.