An independent market monitor stated that the Texas power-grid made a critical mistake that resulted in $16 billion in electricity overcharges last month, and recommended that the charges be reversed.The monitor concluded that Texas kept wholesale prices high for 33 hours longer than warranted as the state dealt with a massive winter storm that led to power shortages and mass blackouts and should correct this mistake by subsequently repricing its wholesale power market for that period. A Public Utility Commission of Texas spokesman said the issue was slated for discussion at a scheduled meeting on Friday. A reversal of the charges would be a benefit to many participants in the market-from retailers to electric cooperatives, wind farms to multistate generators-that suffered significant financial harm when they needed to buy power at the peak price of $9,000 per megawatt hour. The monitor’s determination caps an uproarious week that has tossed the electricity markets into a slow-motion meltdown. The chairman of the Public Utility Commission of Texas, which regulates the markets, resigned. The chief executive of the nonprofit that runs the market was fired-not long after his organization, Ercot, stated that it was $2.5 billion short in payments.