It's not possible to estimate nested pattern loops entirely correctly (100% correct prediction would lead to possible infinite loops), but non-nested pattern loops should be calculated perfectly. However, please provide an example module to have a look at, and I can check whether it would be feasible to predict its song length more accurately.

I thinks no need example module I making those sounds with which i have saw this problem together with microtuning option so no sound values without .tun but I found out that this problem occure when sbx is using on 2 or more tracks so this is only need to know plus printscreen.

The screenshot is of no help. Please provide the actual module to have a look at.

Why i can't upload module "File type not allowed for uploads"
but anyway try makes on 2 or more tracks sb loop block and compare it estimate option with rendered time of module. are you there

You have to compress the file (zip, 7z) to upload it.
And no, simple nested loops on two channels are still estimated perfectly here. However, just to say this once more: <strong>Multiple complicated nested pattern loops are not and cannot be estimated properl</strong> - otherwise the risk of an endless loop during song estimation (i.e. program freeze) is possible.

supplement to last print to make complete this
so in my sys estimate is wrong maybe fault of my cpu | :

The case depicted in your example screenshot should now be fixed in r4312. However, Some more edge cases will not be calculated properly, and for the technical reasons described above, probably will never be.