Oral does not depend on the stomach at all.

Oral is absorbed "passively" in the small intestine.

When oral fails, it is most likely being done wrong.
You must take it alone, on an empty stomach 1 or 2 hours before any food. Presence of food with it will prevent absorption.

I'd suggest you invest in 5mg oral methylcobalamin and use it daily on an empty stomach, and for 3-4 months and then get a new test to compare.
examples of online types:
http://www.iherb.com/Search.aspx?kw=methylcobalamin

And next time you see Dr. Latov, tell him I am very disappointed in his book...there are TWO recommendations for B12 for 500mg in two places in his book !!! Now I assume this is a typo, and was not proofread. If he meant 500 mcg...that is NOT enough IMO to bring up serum levels.

I have seen so many doctors who order weird amounts of B12 oral. In nursing homes a common one is 1000mcg MONTHLY orally...just like the shots. This is just nervewracking to me.
They don't understand how the B12 works by passive absorption, or anything! Passive absorption is very low if stomach acid is poor for any reason, or intrinsic factor not working anymore. One needs daily high doses to make up for these facts. Most is never even absorbed into the body at all.
And if food is present including fiber...NOTHING may get into the blood stream! (This has been shown to be the case with drugs used in microgram amounts-- levothyroxine and digoxin.)
Those drugs have to be taken on an empty stomach too.