In that case.
A few possibilities.
If you want it anchoring and scale up from a corner. Or directly from the centre of the left position.
Add one of the following to your AE project to it’s anchor point.
Left/Top Corner
r = sourceRectAtTime();
[r.left,t.top]
Left Centre
r = sourceRectAtTime();
[r.left,t.top + r.height/2]
Left Bottom Corner
r = sourceRectAtTime();
[r.left,t.top + r.height]
This will fix your anchor point and when you scale it will stay in the position you have assigned it.
Now based on your message you are scaling in Premiere as in using the scale in Premieres effect control. If you are in CC 2017.2 (I think, it might be an earlier version. I’d use Essential Graphics and add a slider control to your scale layer). If you are on an earlier version that hasn’t got Essential Graphics. There’s still away but it’s a but more awkward.
Create a text layer. Call it scale.
Then in Scale of your text add the following.
s = parseInt(thisComp.layer(“scale”).text.sourceText);
if(isNaN(s)){
s = 100;
}else{
s;
}
[s,s]
Make sure you have check template for use with Premiere if you are on a version that doesn’t let you export as a text template, which is in export if it is.
Then in premiere in effects control when you bring it in, it should have an additional section called Master control next to the effects control tab. This will allow you to type in the scale number you want from 0 – I think 10000, I can’t remember what the max number is. If you happen to put text in it though “TEST” for example the above expression will default to 100, but it doesn’t recognise it as a number.
There’s a few other ways to do this, but the above two are the most efficient ways, Essential Graphics being the main one, but I know at home I’m stuck on CS5.5 so I have to do it the second way and both work flawlessly.
If you decide you want the anchor and position to change. So it scale up from Top Left, Bottom Left or Centre. You’ll have to adapt the anchor point expression and a position expression, then again a a checkbox or text box, or even a slider control that will change on command.
Dynamic link can only do so much in Premiere from After Effects and it doesn’t understand the individual layers, which is why you are having your problem.
Hope the above helps. If not I’ll try and break it down a bit better.