Birkat HaMazon has full and short versions similar to Hallel and Half Hallel. For Half Hallel, entire verses 115:1-11 and 116:1-11 are eliminated. However, for Birkat HaMazon short version, parts of verses are eliminated, not entire verses. Why did they eliminate partial verses (i.e., words within verses) rather than entire verses? How did they decide what to eliminate in Birkat HaMazon? It makes it very difficult to compare the full vs the short versions.