A DO probe is calibrated in air at 1 atm to read 100 air sat

A DO probe is calibrated in air at 1 atm to read 100% air saturation. What will it read in pure Oxygen, in 4 psi overpressure, and under a hydrostatic pressure height of 8 ft.

1 atm pressure scale means 14.7 psi. For a probe calibration when reference is given we have formula. Let z be the probe and zold is previous reading, znew is new reading and h is height then New probe calibration reading will be 2.7