What is the difference between these 1 Credit simple searches vs 2 Credit?

The differences are the time of expiration of data:

Simple (1 Credit per ASIN ): Reverse ASIN Keyword Search (Only Keyword Position Ranks are given) - Data is Always Fresh from the Database (Search/Data Expires in 1 Week)

NEW!! Simple (2 Credits per ASIN ): Reverse ASIN Keyword Search (Only Keyword Position Ranks are given) - Data is Always Fresh from the Database (Search/Data Expires in 1 Month)