I do this myself, so I wonder if when humans are trying to minimize impact when communicating bad news, we pick language intended to diminish.

Why say "LESS THAN 1.3 percent" instead of just saying something like "1.28 percent?" You're already giving decimal-level precision. Why does "less than 1.3 percent" sound better for news like this than "over 1 percent?"

For the reasons you mentioned, I assumed that to meant some decimal between 1.2 and 1.3 percent. And rounding the the tenths is more than enough. I didn't quite take that to mean anything sinister, though I'd have probably worded it something like 'just under 1.3 percent' to express that, if for the reason above.