First, the original algorithms of different softwares are different and have errors, but not as much as 1%.

Second, are your two contracts the same?

Third, you can try to overload the data. Some software circuits have problems and data is interrupted.

I read your instructions carefully,

It should be like this. Futures have closing price and settlement price. For example, yesterday's closing price rose sharply, and the closing price was much higher than the settlement price. If there is a rise at the opening of the next day, the increase is not big, but the pattern you see in the histogram is a decline.

Because the opening price of the next day is based on the settlement price,

Give a numerical analogy.

The closing price of soybean meal is 4 100, and the settlement price is 4050.

The opening price of the next day is 4080.

On the K-line chart, the decline is because the closing price is higher than the opening price.

But the software shows that it is rising, because the opening price is higher than the settlement price.

I hope it helps you.