Does anybody here use Ilfosol 3 in a 1+14 mixture and can share their experiences? According to the Ilford technical document: "ILFOSOL 3 is supplied as a liquid concentrate normally diluted 1+9 for one-shot use. ... For greater economy it can be used with many films at a higher dilution of 1+14 with only a small trade off in image quality." What exactly does that bolded part mean?

The reason I ask is I'm trying out some FP4+ soon and the development time at the 1+9 dilution is 4m15s, which is far below what is commonly considered to be the minimum time for development in trays (5 minutes). At the 1+14 dilution the time increases to 7m30s, which is fine. I guess another option is to use the 1+9 dilution, but drop the temperature until the development time is above 5 minutes.

Any and all thoughts would be much appreciated. Thanks.