Power Class Question

Hi! We are using a BG95-M2 and I noticed in the datasheet it shows it to be a Power Class 5 device with a maximum power output of 21dBm. I am confused because as I review the GSM deployment guide, Power Class 5 has a maximum output power of +20dBm. How is the BG95-M2 rated as a PC5 modem if the maximum power for PC5 is +20dBm?

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Thank you so much for your assistance!