Of course if they were being operated just a fraction too rich and did that.....yes you may have a point.
I doubt they will be operating LOP Jaba. They will more than likely be setting a fuel flow for climb and a fuel flow for cruise which will be on the rich side of peak. When I operated these engines in 310/350 combos I would lean straight to a fuel flow too. Been a while but it used to be 27/28 GPH on climb and 17/18 GPH for cruise. If you peaked the EGT you could get it down pretty low in cruise but 49 LPH on a TIO-540 seemed a tad dangerous to me. You can never trust those old EGTs.
If they had GAMI injectors and a full FADEC setup perhaps. Something tells me that won't be happening anytime soon.