The FCC allows a maximum power of 4 watts output. The maximum allowable modulation is 100%. So, What's' the problem ? Most manufactures don't check every radio. So to keep the power and modulation limits inside the FCC guidelines, the actual power and modulation are less then allowed. Sometimes greatly less. If for some reason these limits are exceeded, the FCC can shut down the manufacturing process or pull the FCC Certification.
In the past 25 years we have seen outputs as low as 2 watts and severely limited modulation of 30%.