Yup the lack of tool/shortcuts to easily do post edits while in sentence mode makes using sentence mode annoying.
LingQ should at least add some buttons to quickly nudge the in/out point while consuming lesson in sentence view instead of going to edit sentence mode every time or improve edit sentence mode such that we can also consume a lesson while in edit sntence mode, updating stats lingq and etc.
I currently use @roosterburton lesson editor which he built really fast. It is much faster to edit timestamp in this tool visually with the Waveform but it still takes a bit of time. So I consume lesson extensively here while editing. I use TAB and Shift TAB to jump around sentences and up down arrow key to adjust the time.
If you have any suggestion to make the process faster you can suggest to Roosterburton in the thread below.