I ran across this at an Aussie banana site. I wonder if you have late fruiting if bags might give you faster ripening?
Frequently asked questions about planting bananas | Primary industries & fisheries | Queensland Government
"In southern Queensland and New South Wales the insulation of the cover is essential for enhancing fruit quality during the cooler months.
Bags can also increase yield by 5% to 25%. Temperatures under the cover can be 2°C to 6°C warmer, and during the cool times of the year this can increase fruit length and hasten fruit filling (harvest 4 to 14 days earlier). The yield benefits are much less during the warmer months and special care needs to be taken to avoid sunburn under the covers during these warmer months. This involves the use of reflective silver covers and pulling down a leaf over the cover. Perforated covers are commonly used to reduce sunburn damage for export production overseas."