I would most humbly suggest (I have to say that else I get jumped on for daring to have an opinion) the following regarding Chelsea Pensioners may possible with luck answer your query:
During the reign of King James II, the Royal Hospital was still under construction, so he introduced a system for distribution of army pensions in 1689. The pension was to be made available to all soldiers who had been injured in service, or who had served for more than 20 years.
By the time that the Hospital had been completed, there were more pensioners than places available in the Hospital. Eligible soldiers who could not be housed in the Hospital were termed out-pensioners, receiving their pension from the Royal Hospital but living outside it. In-pensioners, by contrast, surrender their army pension and live within the Royal Hospital.
In 1703, there were only 51 out-pensioners, by 1815 this figure had risen to 36,757.
The Royal Hospital remained responsible for distributing army pensions until 1955, following which the phrase "out-pensioner" became less common, and "Chelsea pensioner" was used largely to refer to "in-pensioners".