I imputed 2 of my W2's (mine husbands) and was at a refund amount of $2600 (including child credit). My husband received another W2 and when I entered that, it went down to $1800. That W2 put us at a little of $50,000. Is that why it went down? He claimed the same on both W4's, so I don't believe he would owe Is it a higher tax bracket over $50K? If so, that really sucks.
I know it sucks, but your tax return was invalid until all of the W-2s were entered. The tax return is based on the entire year's income, not any given W-2. Unfortunately, the software packages such as turbotax like to project your refund the whole time and give you teasers between each W-2. This gets you excited and then disappointed as the last W-2 is entered. 1. Yes, the more you make, the higher the tax bracket. You are your husband are in the 15% tax bracket. 2. the W-4s were fine. Even with the last W-2, you do NOT owe. My goal was always less than $500. You are getting $1800.
Tax brackets are based on combined income. However, withholdings are based on only the income the employer sees. So if the three incomes were all in the say 15% tax bracket, that's what your withholdings were based on. However, added up, the total income could have been in the say 20% tax bracket and that's what you are taxed on, which means lowered returns. First three tax brackets are at $11,000, $43,000 and $112,000. Most likely, all your income was taxed at the below $43,000 rate and your husband's second job put you over the $43,000 after deductions.