I hate to burst your bubble, but if you got a credit limit of 3k you did not get approved for the cash+, they did to you what they do to everyone who doesn't qualify and started you off on the platinum rewards card, its a measly 1%.  Also, I'm not sure where you are getting the 6.25% on the cash back for that card anyway, it tops out at 5%, and if you have a platinum checking with them you get a 50% bonus(based on the 1%, which adds .5% to both the 2% catagory and 5%), so the most you would accrue is 5.5%.  Nevertheless, its a signature card and with 3k limit they didn't approve you for it.  Impressive on the other 2 cards though, congrats!

Bubble not bursted.  With US Bank, I applied directly through a rep because there were a few concerns I had in regards to the card.  I was worried that since it was the third card I applied for, my credit rating already had taken a hit and I should wait on applying.  My main concern was that I did not want the downgrade if I was not approved.  I was instantly approved and the rep assured me that it was for the Cash+ and not the downgrade.  

I get the 6.25 based on the fact that if you cash out in increments of $100, they give you a bonus of $25.  With a base of 5%, that increases your cash back to 6.25%.