Working with the time grid on the iPad is a nightmare, so when you look into this, please consider the overall problem. For example, it's wonderful that you can put 4 charts (or more) on the iPad screen (or even iPhone).... but, it is almost impossible (and incredibly frustrating) to set all of them to the same time grid so you are examining similar time frames for all pairs. The "pinch zoom" is just so fiddly that you give up in frustration.

I'd suggest that you consider having a way to add to the "Timeframes" menu an option to set the grid to a fixed number so you can easily apply it to every chart. I would also suggest that the timeframe not "compress" when a chart is made larger or smaller. For example, when a chart is full-width, then you switch to a layout where the same chart occupies 1/4 of the screen, the timeframe should not "squeeze" to a tiny amount but remain fixed so that you can shuffle and rearrange without suddenly having miniscule candles to zoom.