They will get your #'s immediately but takes awhile to actually become active. If not active #'s are pointless. You can do same thing yourself but save money. Once you obtain your MC # you will be put on FMCSA register within a week for protest for 10 days. This is so if you have been bad before people can protest your new authority. Mine became acive at 20 days. I know GLauthority.com tells you 5-7 weeks. There are steps you have to do though before you get active. You have to have to BOC-3 on file (usually can do for $25 if thru agent), qualifying insurance sent to FMCSA from you insurance. They have to do it, FMCSA will not accept directly from carrier. You can go online and do MCS-150 easily and quickly. UCR can be done online also for nominal fee (will be same if snail mail, depends on # of trucks you have). You can get IFTA forms online and fill out, an AUD-29 has to accompany that. My IRP account was made at IRP office when I got my plates. You can also get your apportioned plate applications online so you can have filled out and ready when you go in to IRP office. It cost me $2600 for 2 trucks here in Kansas. Have 40 states, no far northeast or Northwest, no Mexico or Canada on mine. I also have mine tagged in Kansas to 85,500 so that bumps in all state to max weight which ups cost. I know I am forgetting stuff but it's early, lol.
BTW if you are flatbedding in Kansas area I can get you pretty decent paying loads going to Texas or Colorado. CO not as many, TX is plentiful. I pay (Im car crusher too) $45/ton to goto Midlothian TX (Dallas suburb), thats $1,125 on 24 ton load. You get paid thru my car broker (they pay exactly what I say) and they pay anyway you like. Comcheck, bank wire, whatever works, and do immediately.