Decibals as measured on an "intensity" level is more a lab/engineering scale than SPL measurements adjusted for the human ear. Instruments are able to consistently measure "intensity". But for human ear purposes, the variance in each set of ears and how the human ear amplifies certiain frequencies, makes this measurement inconsistent.
Most SPL meters are adjusted to compensate for the human ear and closely mimic an average range as interpreted by the human ear.
If you take those same decibal levels and measure them on a scientific instruments on an "intensity" scale, the results would be more scientifically accurate. But not really important for the purposes of developing consumer products. Human perception is more important for this purpose.