You have chosen to sponsor your bid up to a maximum amount of .
Check -> http://126.96.36.199:5000/
Now click on tab 4, or 5.
As you can see, there are no "subtabs" there.
Tabs 4 and 5 were added calling the already done "AddTab" function at the end of the page.
All you have to do is a function to add the "SUB" tab there.
After that a RemoveSubTab should be called to to remove the dynamic subtab you added what wouldn't be a problem.