My friend,
I found this at FCOM VOL2, page 7.20.10.
¨Inflight Starting
Note: At low N2 values (¨RPM below 8%¨), the oil scavenge pump may not provide enough pressure to return oil to the tank, causing a low oil quantity indication. Normal Oil quantity should be indicated after start¨
Page 7.11.17
¨ Note:Indicated oil quantity may decrease significantly during engine start, takeoff and climb out. If this occurs, ENGINE OPERATION IS NOT IMPACTED and the correct oil quantity should be indicated during level flight¨
Check quantity before start, check pressure after start and
ENJOY NG!
I hope it helps