Hi Didimo this is known to happen in some cases (ERJ 145 comes as an example) whereby you have throttle profile settings like T/O G/A, CLB, CRZ etc.
If the wrong setting is chosen then max power will be translated to the max. available by the profile.
F4 however, overrides this thrust profile setting and so you can achieve the 100% thrust.
This is mostly a freeware issue although the ERJ-145 as I said also has this. Now that I think of it, the EuroWings 2004, BAe146 is also the same.
Just my two cents.