Dell XPS13 9360 with i7-8550u: can't set higher PL1 Limit

[emc02]

Hello, first I want to say Thanks or this great tool! Setting the undervolting works perfect.
I don't know if setting higher PL1/PL2 Limits and times is possible on XPS13, but I wanted to tell you my tests and results.

On setting everything (Power and time on PL1, PL2 and PP0) to MAX_POWAH then it looks like this

but the PL2 and PL1 Limits are still the same at 51W and 23W like stock.

On setting the values (Power and time on PL1, PL2 and PP0) to absolute values like:
pk->EnableMsrPkgPL1 = 1; // Enable PL1
pk->EnableMsrPkgPL2 = 1; // Enable PL2
pk->MsrPkgPL1_Power = 23000; // PL1 in mW or MAX_POWAH
pk->MsrPkgPL2_Power = 51000; // PL2 in mW or MAX_POWAH
pk->MsrPkgPL_Time = 28000; // Tau in ms or MAX_POWAH
pk->ClampMsrPkgPL = 1; // Allow clamping
pk->LockMsrPkgPL12 = 1; // Lock after programming

results in 3W Power Limit and 400MHz (so I think that's a security setting used if something is wrong?)
or could the value of the numbers be wrong? (I build it with Build-PowerMonkey and x86 shell because x64 shell throws errors.

On setting only the undervolting and ignoring everything else:
pk->planes[IACORE].VoltMode = V_IPOLATIVE;
pk->planes[RING].VoltMode = V_IPOLATIVE; // V_IPOLATIVE = Interpolate
// V_OVERRIDE = Override
pk->planes[IACORE].TargetVolts = 0;
pk->planes[RING].TargetVolts = 0; // in mV (absolute)

pk->planes[IACORE].OffsetVolts = -106;
pk->planes[RING].OffsetVolts = -106;// -50;        // in mV 

everything works as expected:

Maybe you have an idea what could be done or tested to "unlock" the Limits to 28W or 35W (I have watercooled my XPS13, so I could use much more power ;-) )

edit: in Screenshot it shows Limit of 28W, but it's always limited to 23W
The 51W are limited to "VR Current" on undervolting, but that's ok.