USB power delivery

My Precision 3480 has a switch in the UEFI to set 7.5W or 15W of power on the secondary port. My Assager USB cable has power meter and my iPhone 15 Pro does pull 15W of power. Sometimes windows complains not enough power suggesting the UEFI option may need to be bumped up to maybe 20W or 30W to handle mobile phone charging,.

USB PD standard supports flow through so my 130W brick has enough to go around. USB PD is designed to handle more power but Dell et al seem to be sluggish at supporting the standard,