There's no doubt there are pilot weather reports (PIREPs) that are extremely helpful and those that are not as helpful. As shown on the EZWxBrief EZMap below, here's a perfect example of two icing PIREPs to the southwest of Nashville, Tennessee just 10 miles apart; but for their utility of the icing threat, they are light years apart.
The southern PIREP from a King Air 90 (BE9L) shown below reported light light icing at 1055Z, but notice that the altitude is UNK (unknown). This is because the flight level (FL) is missing since the PIREP only indicates it was taken during the climb (FLDURC). Yes, the pilot reported bases at 4,000 feet and tops at 6,000 feet MSL which you might likely assume are the altitudes that icing was being accreted on the airframe...but you don't know for sure from this report.
BNA UA /OV 20 SW BNA/TM 1055/FLDURC/TP BE9L/SK BASES 040 TOPS 060 /TA 0/IC LT RIME