The industry uses the days till maturity very deceptively. Generally, if they say start your seeds 6 weeks (42 days) before last frost and matures in 120 days after transplant, they mean 120 days plus 42 days, so 162 days after the seeds are planted. However, they also sometime do same and say till maturity rather than till harvest. So 162 days till they set flowers which can be a couple months before fruit is put on. Then there is growing conditions. If it is too warm at night, flowers will drop and no fruit will be produced until later in the season when things cool down a bit.
I am going to use the Carolina Reaper as an example because I know I am listing the information from the person who invented the thing. The page at the Puckerbutt Pepper Company says the thing can mature in as little as 70 days. Now think on that, a Chinense that goes from seed to mature fruit in 70 days?