thanks a lot for the answer!!! sure I will explain better:

nothing, i am not interested in the missing interval but I have to fill it somehow in order to give it consistency so it can be filled with the value 'mean pressure' of the above interval, in this case, the missing interval
06:21_06:52
?
08:14_08:31
can be filled with 1019,25

and here lies the challenge.... the rule is that I am only interested to apply the value "mean pressure" in the 'pressure' tab into the 'results' tab , and only apply the the available value (1019.25) within the same time frame, and the missing time gab, can be filled with the value before or after...

another issue : I was also looking for a way to reduce the number of points in the tab 'results' , basically i just want to have 1 value per minute , and erase the duplicates..... any suggestions about this too? I tried with this =IF(MOD(ROW()-ROW(C$1),$D$1)=0,B6,NA()) which basically puts the value from column B into column C at the frequency indicated in cell D1, and as in my case, there are 6 entries per minute, i put 6... the problem is that it delivers repeated date cells every x interval... quite a pain... I tried also with an advanced filter, to remove duplicates... didnt work.