If I did the math correctly your commuting amounts to ~920 miles per month (46 miles per day * 5 days per week * 4 weeks = 920 miles). Even if you drive an extra 50 miles per week this still only amounts to 1,120 miles per month.
5 quarts of conventional oil + an oil filter = about $15. A three month OCI would amount to $30 every six months.
5 quarts of PP + a decent oil filter = about $30 (less if you buy the 5 quart jug at Walmart or use rebates).
Why not use a good Group III based synthetic, such as PP, and a Wix or K&N oil filter? The protection and cost will be the same and, as an added benefit, you will only need to use a six month OCI. The cost will be equal to, or less than, using a three month OCI on Conventional oil. Your OCI will amount to anywhere from 5520 to 6720 miles every six months, which is very reasonable. If you have concerns about going six months, collect a sample and perform a used oil analysis to see how your oil looks.
Just my 2 cents.