Base maps are used for tuning, and may be anywhere between 16-20psi depending on the tuner, it's not an issue. The Cobb OTS maps are 20-22psi range between the 91 octane stage one and 93 octane stage 3, and there's a description provided on the map sometimes providing reference to what the boost may be... but the tuning isn't based on a boost target's per se... but there are absolute limits set withing the software for safety reasons... the ECU logic isn't hitting a boost target, the boost logged is the result.
Here's the description as an example from the OTS COBB file: "Map Switching Enabled, Slot1 - Performance, Slot2 - Economy. Intended for an otherwise stock Fiesta ST vehicle with a stock exhaust, and a stock intake system. 91 octane fuel minimum (95 RON). Boost Targets: ~20.5psi peak boost pressure tapering down to ~13.5psi by the 7000 RPM redline, +/- 1.5psi. Flat Foot Shift Enabled (5000rpm). Fuel and Throttle Cut LC Enabled (2500/4000rpm). Burnout Enabled (5000rpm)."