"PL" is just Motorola's proprietary name for "CTCSS" (Continuous Tone Coded Squelch System).I'll add that I just got district 1 at 136.5, too.
 I should note that my scanner (436HP) specifically shows PLs as "PLXXX.X". Manual states that "CXXX.X" can be CTCSS, DCS, and something else (can't remember). If the 136.5 is indeed a CTCSS tone, I wonder why there are two ways of showing that. Perhaps the "PL" is reserved for amateur frequencies? Meh, I digress.... a question for the uniden tech forums I suppose.
It is just how it is interpreted. PL, CTCSS, C, C.TONE, etc... They all mean the same thing.Sure, but my scanner doesn't know what radio the signal is coming from. So why do some signals say "PL67.0" and others say "C136.5"?