Precancelled Twice - Two Very Different Precancels

Scott 815 with Oakland California type 243 AND Oakland California type L-8 IHS.

At first glance, it appeared the Local precancel might have been L-17 HS, but there is a faint date at the top, making this an integral precancel, and most likely L-8 IHS. Perhaps the second precancel was applied to meet the requirement that all denominations above five cents were dated. If this is the case, the second precancel would have fulfilled that requirement. Following that line of thought, the Type 243 would have been applied to stock before the required date and not used up prior to it. Anyone have any thoughts on this?

your supposition is correct, these are fairly common