Jaime Hernandez: In 1972 the Philadelphia Mint used three slightly different reverse dies to strike circulation strike coins. It struck a Type1, Type 2 and a Type 3.
All three Types illustrate a round outline of the U.S. and other surrounding countries on the reverse of the coin. Some of these surrounding countries are the Islands of Cuba, Jamaica, Haiti and the Dominican Republic, which are shown just South of Florida on the reverse of the coin.
On a 1972 Type 1 Eisenhower Dollar reverse, the island of Jamaica is only shown towards the South East but in reality, it should also be illustrated towards the South East side of Florida. This is probably one of the reasons why the Mint decided to modify the design along with the fact that the Type 1 was struck with a low relief design.