That’s a great question. These numbers are displaying 2 different things. I personally feel that the web dashboard number isn’t really useful, especially on older nodes. But let me break it down.
The web dashboard simply shows the lifetime percentage of successful audits. On relatively young nodes, that does still give some indication that something may be wrong. But if my node is a decade old. I will be disqualified before that audit % even drops below 99%.
The reason for this is that the disqualification system uses an audit score that represent the nodes recent performance on audits. There is a lot of information on this system here: https://github.com/storj/storj/blob/a6f0be2047a9f8c77b86f1b6ffdadb8c6375a6df/docs/blueprints/node-selection.md
The formula used results in a value between 0 and 1 that displays your audit reputation score. If that value drops below 0.6, you will be disqualified. For the earnings calculator I simply chose to multiply that value by 1000 to make it more human readable in the limited space. More detailed reasoning can be found here: Earnings calculator (Update 2020-04-10: v8.2.0 - Price and month estimate)
tl;dr: The dashboard shows lifetime success percentages. The Earnings Calculator shows a score based on recent performance that is actually being used for disqualification.
On a new node I would still take a look at what happened to get audit failures to begin with. They should basically never happen. But if the earnings calculator shows 1000, you’re in good standing currently at least.