I'm afraid I can't shed much light on Casper Bittner, but my ancestors came from Germany to Pennsylvania, then to Maryland as well.
Phillip Bedinger (also spelled Bidner) immigrated from Germany (location still unknown) to Somerset PA. He was born about 1745 and d 15 Apr 1816. From my understanding, the differences in surname spelling were mainly due to variations of those who attempted to write the spoken name. However, my GG-Grandfather, Mathias Frederick Biddinger, intentionally changed the familial surname, which was spelled "Bittinger" by his father and grandfather. The main reason for changing the spelling was that his parents and family disowned and shunned him after he and his wife joined the Latter-Day Saint (Mormon) Church. He immigrated west, to Manassah Colorado, changed the spelling of the surname to Biddinger, and never contacted his family again.
Although there are many possible reasons for variations in spellings of surnames (many immigrants could neither read nor write), these are the reasons for the variations for surname spelling in my family line.