Coins per day (Daily Est. Rewards) = 0.001032308*14.3077 = 14.7699486 DCR coins
Using the same inputs WTM Calculator shows Daily Est. Rewards = 14.715472 DCR Coins
I know that the difference is very small, but would like to still figure out who is wrong here.
Your calc seems to be spot on, though as core I am using a bit different formula.
14.3077 * 86400 / 2**32 * 1000000000000 / 19486988.241 = 14.76994858
In addition to that wtm takes into account difficulty increase from your hashrate, thats why onsite value is a bit lower.