Multiple Amount Field

I have an issue with PMF I'm working on. 

In the form, I have multiple Amount Field:
Amount 1 (required)
Amount 2
Amount 3
While everything is being totaled correctly, the issue is the display on Amount 1.
It only happens when I use a comma to indicate thousand.

Example:
Amount 1 = 3000
Amount 2 = 2000
Amount 3 = 1000
Total will be 6,000.00 and the history will also display all amount correctly in 3,000.00, 2,000.00 and 1,000.00

BUT, if I enter amount with a comma
Like:
Amount 1 = 3,000.00
Amount 2 = 2,000.00
Amount 3 = 1,000.00
Total will still be 6,000.00 and BUT the history will display amount like this 3.00, 2,000.00 and 1,000.00
Again, still the total is 6,000.00

There's a difference in entering with a comma.