Bollinger bands says whether price or any source is relatively high or low at any particular point of time. We can apply Bollinger bands on RSI and volume indicator Price Volume Trend to identify if RSI movement or PVT movement is relatively high or low.
By calculating Bollinger %B, we can define the variation in a range between 0 to 1. By applying Bollinger %B on price, volume and strength, we are trying to compare how much they differ relative to each other.
For example, if Bollinger %B of volume is higher than Bollinger %B of price, which may mean, we can still expect continuation of upward movement. If volume %B is lesser, we can interpret this as price has moved more than the volume and may retrace back.
Note: I tried adding multiple volume/strength indicators as input choice. But, if condition did not work with simple string. Have no idea why. I will try adding that later if more people show interest.