The valuation for your complete sheet is probably accurate. Strangely, it would be worth a few pennies more if broken up. Some people collect traffic light blocks like this bit... (check out where the arrow is pointing also as there is a variety (spot on hand) again worth a little bit extra.

The six stamps below are the cylinder block and will be collected by some as well. Of course the stamps must be clean and perforations intact to have any value as a block.
