Thanks for all your answers, just one doubt.
What is the Pro savings account, is it the account where the MAB is 20,000??
Also what was the Signature Roayal Credit Card Credit Limit at time when you got the upgrade?
I'm sorry I'm giving your answer late but yes, please upgrade to White since it is their Top most card with most of the benefits. But please check if the card is really on LTF offer & get it documented in Black & White from them properly. I know some person where in the Pre-Approved offer it was given as LTF but later the Annual Charges were applied. It was a hard time for them fighting to make this card as LTF.