Not a common profile, the LSP is intended to eliminate or reduce the occurrences of voiding. The slope is similar to the RSS profile but with the soak segment at a lower temperature and for a longer duration. It may be successfully used in an R&D environment.
I have used this profile when there is limited data on a product or on a first pass of a new product for which the process is not well understood. It is a good profile to use when characterizing a new process. The LSP profile will provide an indication of interaction amongst oven, PCB and components with the solder paste.