Will H1B amendent due to location change affect H4 Dependent VISA yet to be started

Hello Team I am a H1B VISA holder currently located in Jupiter, Florida (H1B is sponsored by Company).Got married in INDIA in February and had decided to start H4 VISA process for my spouse After return to USA on March 2015 due to project requirement I was supposed to move to Milwaukee,Wisconsin. Company Filed for my LCA change and LCA was approved on April 2015. As per new USCIS policy (9th April) alongwith the LCA, H1B petition has to be amended. I have sent the documents to my company and company will start the process for petition change. 1. Will I be able to start my H4 VISA process for my spouse after petition is filed to USCIS? 2. If yes,will it be special case. (Extra documents?) 3. if no, as there is no pre-defined ETA by USCIS. which means should wait for 6-7 months? Thank you!