How to accurately set small track delays (is this a bug?) and/or otherwise make small timeline adjustments?

Hello people,

I'm pretty new to Logic and coming more from an audio recording/mixing background, rather than midi/composing, I'm struggling a bit to find how best to approach some things, especially to do with the timeline.

The particular activity that triggered this question was an attempt to accurately tweak the position of some raw recorded tracks in order to time-align the audio (multiple miking scenario with different distances to each mike). This is something I do relatively often and typically know how much I want to shift the track in advance (at least as a starting value) based on the known distance between the microphones. In this attempt I already knew that I wanted to slip one track by 4.6 milliseconds.

First I thought I was going to do this using the track delay value in the inspector area, so I ctrl-click and set it to 'delay in ms' and then double-click to edit the delay value, write in "4.6" and press enter, and it keeps changing my value to 23.9. Hmmm. Checking the value selection menu to the right of this field I see there is a coarse range of values associated with fractional note lengths but none of the values goes below 10 and '23.9' is not in that list. Is this a bug or what is happening here? Reading between the lines of the help text in the manual it may be that this feature does not really do what I thought/wanted. But then I found this article at http://www.apple.com/uk/pro/techniques/recordingdrums/ where it says "You can recreate this effect in Logic Pro by adding a tiny amount of delay — say, five or 10 milliseconds. Simply select the ambient sound tracks in the arrangement and use the Delay parameter in the inspector to increase or decrease the amount of delay." This seemed to confirm the general idea so what am I doing wrong / what's going on here?

Next I come up with a new cunning plan of editing the start time of the region in the event list. Now I find that the start times are expressed in Bar/Beat/Division etc. which is not much use when I just have some amorphous blobs of recorded audio. I find the menu item to change the view to show it in SMPTE Hrs:Mins:Sec etc. but the fine grain control is now evidently in Frames and Subframe values (is it "Bits" ?). After more googling, reading manual etc. I conclude that logic seems to work with 80 subframe divisions (0-79) and I eventually find I have a frame rate set to 25fps. 25x80=2000 so I assume each frame subdivision is 0.5ms and so I need to shift the track 9 subdivs to get approx.4.6ms delay. In the event list the start of my track region is showing as being at position 01:00:00:00.00 so I change the last part of the number so it says 01:00:00:00.09 and press enter. It changes my value to 01:00:00:00.08 ! I see the region has moved to the right in the arrange window. Looking (at max horizontal zoom) however the start of the region is lined up with a point about 2/3 of the way between marks 0:00:00.07 and 0:00:00.08 on the SMPTE ruler - not even .08 let alone nearer my .09 . If I then grab the region with 'click-hold' (but don't move it) I get the 'Move Region With Automation' box pop up. But this box then shows a different set of numbers again for the start point and length of the region - it says the start point is 01:00:00:00.0194 the last part of this number suggesting that logic does not after all divide the frame into 80 bits/subframes? But whatever it is this value does not seem to align with the ruler value which in turn does not align with the event list.

By the way, I have 'Snap' set to 'Samples'.

I find I can click-drag the region to start <almost> at the ruler mark for 00.09, either just before or just after (seems maybe a sample length is 3 'marquee ruler marks' with the boundaries not falling exactly on 00.09), and the event list then updates itself to also say 00.09 now (regardless of whether it is dragged just before or just after 00.09 on the ruler)!

The new position is now shown in the click-hold pop-up box as at 00.0225...

I looked briefly at the sample editor as another possible way to slip a track by a known amount but couldn't see an obvious way to do it there either.

What's going on with with these confusing numbers and any recommendations on how to approach this activity in general ?

TIA

/Henry