To put this in perspective for investors, here's a chart of LIBOR vs time over roughly the same period.

LIBOR has gone up approximately
2% during this time.
Has the interest rate on an LC A1 loan gone up 2%? No.
Has the interest rate on an LC A2 loan gone up 2%? No.
Has the interest rate on an LC A3 loan gone up 2%? No.
...
In all cases, not even close.
You have to get into the C/D/E/F/G loans before you see increases on that order, but there we know that something else big is going on. The quality of LC loans in the C/D/E/F/G range deteriorated badly in 2015 & 2016, and those interest rate changes were done to compensate for increased default rates.