Don't understand cams

Yeah i wish it showed advertised open and close but only @.050". Adding 50* to that would make it be close to what i would have expected.
Only cams i have use were MPP cams before now, So they were ease to compare. all were at advertised. trying to compare to other cam manufacturer is just about impossible. I think i read somewheres that chry figure there cams duration and overlap at .002 lift not 0. them you have comp that will give some advertised spec's. But they do them at .006"
I realize that chry is the only one that give spec's strictly by advertise and the standard has become @.050.
It just make it hard to shift gears, so to speak. i had a smaller cam with 280*duration. Now i have a larger cam with 240 esh duration and less overlap (@.050) This and a million other reasons why most, can not pic out a cam without leaving a lot on the table. Just by picking a slow lobe ramp compared to a much faster/ aggressive lobe ramp can make to cams with the same exact spec, perform differently.
That's why i let them figure out what cam will work best for me. " I want a came that make power down low to stretch my 2800 converter, bla bla bla live/race at 6600 feet, don't want to buy expensive valve train part. (don't want to rev over 6500)" Got the cam i posted above and vary happy with it.