Federal Taxes: Allowance Number in W4 Form for Singles

I am a single IT professional who got up in a situation of paying an heavy amount of tax to IRS. This has happened because my employer have shown my moving expenses in my wages to IRS. When I talked to them, they told me that even if the relocation was not taxed, I would only owe <30% so the rest of that taxable amount I owe is not due to that. It is my W4 that has too many withholding allowances.

To confirm this I checked my W4 form and it has 'Allowance' as '2'. I am not sure about this value.

Please guide me here if my W4 is correct per my status.

Federal Taxes: Allowance Number in W4 Form for Singles