AIGB,
First we need to know which page? IF you redirected www.example.com/old-page to www.example.com/new-page and you did so in the .htaccess file, then when using OSE, there are a couple of things to consider: First OSE crawls roughly once a month. The next is scheduled for Valentine's Day. So nothing will show up different prior to that.
Next, once you make the change, it will not be instantaneous. We do this fairly often with redesigns on sites where we are taking over the site and doing the SEO. We just made the switch on one roughly two weeks ago and did a url to url switch (actually to a similar site/ same product). Today I notice that we are up slightly in PA and there are two new links on the new site.
Typically, it will take two to three months to see the majority of the juice on the new url. A law firm we changed in late August shows that all has moved to the new site and the site has higher DA and home page PA than the original. While the old site shows slightly reduced DA and PA (which it will lose over time).
In OSE if you do the search on the old url, it will tell you that hey this redirects to new url. Do you want this or the old one? You can then look at either.
If you did this and it is showing a PA of 1 there is something not correct. I would need to see the two urls to be aware of what is happening. but you should not be seeing any change prior to the update unless the 301 was placed prior to the last one.
Best.