Here's an animation showing the difference between Obverse Design Variety (ODV) ODV-20 (a 1956-P), described as "extremely large letters in LIBERTY" vs a normal LIBERTY, in this case a 1955-D coin. ODV-20 was used on 1956 Cents only. In both cases the coins pictured in the animation are BIEs. The 1956-P ODV-20 is Cohen BIE B649, while the 1955-D regular ODV is Cohen BIE B519. My theory is the mint experimented with larger letters to see if they could stop the BIE die chips from forming, but it clearly did not work and they went back to the original ODV in 1957 onwards.
