That's a normal function of the program. When you enter your first W-2 form into the program, it front-calculates all of your deductions, based on your filing status and number of dependents entered into the program before you begin to enter your income. It's set that way because many people do not have a 2nd W-2 to enter and the calculations for taxes can be based on that one form entry at that point in the program.
When you enter your second W-2 form, you are not then getting additional deductions and exemptions from your filing status or number of dependents on that income because those were already accounted when you entered the first form. It is adding the income to your overall taxable income and subtracting only the amount of federal taxes withheld from that W-2 in the calculations for the running number calculation you see at the top of your screen.
The calculations are not final until you have all of your forms entered and you've answered all the relevant questions for your tax return. If you were completing your taxes manually on paper, you would first total all your income from all W-2 and then subtract the exemptions and deductions based on your filing status and number of dependents. You would then calculate your tax on your income and that would be compared to how much you had withheld from your payroll for federal taxes.
In the program, it does not predict that you have a 2nd W2 to enter and put a hold on showing you the calculations without deductions for filing status and number of dependents until after you have entered all of your W-2 information from every W-2 and other income form you received. The math works out the same in the end. The program adjusts as you continue through each step until all forms and entries are completed, continuing to calculate based on your entries and how you answer questions until you finalize your information and are ready to file.
