Split plate doubling? Never heard of it. I'll have to search it on error-ref if it's on there. Not sure where the twisting effect you see is, but I do agree that it must wear quick, as I didn't really have confidence in this one being a DDO, as it's in about as low as condition as it can before it isn't evident or visible. Probably AU55 or so. Care to elaborate on the twisting effect? Thanks.
Split plate doubling is a form of die deterioration in some cases it will affect all the lettering and split the lettering and date in half. (looks like separation lines) Most of the time it leaves a push secondary doubling that ghosts one side of the devices Early die states of this doubling will not have the ghosting affect and look like this.