Hi All,
Again, thank you for your kind replies.
These issues are a known limitation of float and double field types (esriFieldTypeDouble).
In fact, the bug logged for this issue was closed as a known limitation.
Map service query operation does not retrieve formatting.
This happens because the query operation returns raw data values and does not honor table formatting applied in ArcMap.
Floating-point numbers are represented in computer hardware as binary fractions.
Unfortunately, most decimal fractions cannot be represented as exact binary fractions.
The result of that is the decimal floating-point numbers entered into a double field are only approximated by the binary floating-point numbers actually stored in the machine. The cause of the issue is Double field type.
This is a limitation of Floating Point Arithmetic - https://docs.python.org/2/tutorial/floatingpoint.html#tut-fp-issues
I hope information above is helpful.