Why is that within the same option group expiring the price change varies alot has the stk price increase .20 the option price may increase 0.05, 0.35 and some decreases would loc order allow trader to get the option fill at last price listed?
LOC orders in options are not a great idea. Some options MM executes your order 'near' the close. You have no expectation of getting a good price. You would be better off using limit orders in liquid tight spread options with a minute to go. With less liquid options and wider spreads, give it at least 15 minutes if you need to get out by the close. 1245
LOC = Limit on Close Would not the fill price be the limit or better? If you have to get out by the close I would use Market Orders.
You might not get an execution with LOC. Also, at the close the Best execution, no trade through rules don't apply. For the same reason, you can get a VERY BAD execution with a MOC order in options. I would recommend NOT waiting until near 4pm est.