I think that the OP was asking the following:

If he submits a ticket to support, will they be able to customize the dialplan on his ATA to explicitly support 7-digit dialing (without an extended pause after dialing the 7th digit)?

I can see something like this working if his ATA is a Linksys PAP2T, but can it work for Grandstream? I'm unclear as to their dialplan customization options. Even though the PAP2T clearly allows such customization (and if the other customers' ATAs support custom dialplans), is support able and authorized to make that change?