Unfortunately you are another statistic of the game being played on homeowners. Appraisals can vary by 10% either way so there is approx. $30k variance in how your appraisal can come out. The standards are subjective and subject to interpretation.
With that said if HSBC really wanted to do the refi they could find the other $10k needed.
Here's one better look at your mortgage or deed of trust depending on what state you are in. Look at the first few pages for MERS as nominee...
Then google "where's the note" and 'Kansas supreme court decision against MERS".
It's not necessary to have MERS as nominee but suffice it to say they don't have your original note. No note means no claim, no claim means the bank defrauded you. That means you can force a really good modification or rescind the mortgage for fraud.
I'm in this game every day, personally rescinding 5 mortgages for lender fraud and you need to take the gloves off to beat the crooked lenders at their own game.
You may not believe lenders are that nefarious, but they are illegally foreclosing on thousands of homeowners every day with no standing to do so. That's a fact.
hope that helps