I also get that lag time on occasion, but it doesn't seem to happen often enough to have a great effect on solving time. Nonetheless, it probably does shave a few tenths of a second off my time at the end of the month. I think other factors can have an even greater effect on solving time. Using a notebook can slow you down. You may have problems with the cursor making jumps across the screen as happens with notebooks. I think the flat keyboard slows me down a few seconds on average. I can type much faster with a desktop keyboard, especially one that is curved and ergonomic. I think sometimes a poor wifi signal may pare down your solving time. Worst of all is going to a bar with wifi. After your sixth Martini, you really take a turn for the worse.
joseph k, ne'er-do-well extraordinaire