compression readings

["G. Cook" <litfuse@triton.net>]

Well, my oil usage started upward, so I opened the compression tester I
bought long ago and gave it a go: 145, 160, 160, 165.  (early 70's
vintage motor).
After a squirt of oil in #1, it came up to 150.  I know this has been
discussed in the past, and if I remember right, I'd say maybe the rings
in #1, maybe a valve problem.  Plugs looked fine and indistinguishable
from each other.  The motor is factory rebuilt 10,000 miles ago.   What
is my next step?