PS calculation

Intermediate corp. has asked for your assistance with their earnings per share calculation for the year ended 12/31/2012. They provide you with the following information. They had 500,000 shares of stock outstanding on 1/1/2012. The average market value of each share is $25 for 2012. Their net income for 2012 was $1,200,000 and their tax rate is 40%. On April 1 they issued 75,000 shares. On June 1 they acquired 37,500 shares from the open market to use as treasury stock. On November 1 they reissued (sold) 20,000 shares of their treasury stock. Intermediate has 2,000 stock options outstanding for the entire year. Each option can be exchanged for one share of common stock at an exercise price of $20. In addition, Intermediate has bonds which were issued at par with a face value of $2,000,000 and a 5% interest rate. The bonds were issued on June 30, 2012. Each $1,000 bond is convertible into 20 shares of Intermediate common stock. Intermediate also has 40,000 shares of %6 convertible, cumulative preferred stock ($100 par value) which was outstanding for the full year. Each preferred share can be converted into 3 shares of common stock, No preferred dividends have been declared for the current year or the preceding 2 years. Provide basic and diluted earnings per share calculation.

I posted a same answer here previously, but the guy did not answer my additional comments. I am posting his answer here and please answer my following questions to his answer:

1.Net income should be net of income tax. Why I need to calculate the income tax to the net income again?

2. The bond is issued on June 30. The interest of the bond assumed that I have avoided should be divided by 2. Why he did not divide it?

3. when calculating the basic EPS, why he doesn't minus the preferred stock dividends from the net income?

4. If I calculate the dilutive impact of stock options with the treasury stock method, is the diluted shares 400?