The solcast card is improving, there is no longer a 5x multiplier in the latest update but it looks like there are still snags.
When looking at my data for today at 08:00 (morning) it shows a forecast of 15.29, actual of 0.4 and estimated of 14.95. The 14.95 looks more like what it estimates will be be generated during the rest of the day as opposed to the the tiny amount it should have estimated was generated. The opposite problem can be seen on day -3. Here the estimate is 0.3 and the actual 14.5. The estimate should be very close to the actual as the blue area of the graph is a similar area to the yellow. The blue area of the graph is missing estimate data up to 08:00.
In summary
it looks like on days when there is incomplete data the estimate is calculated incorrectly. It should match the blue area but looks more like the blue area - the grey area.
The estimate for day -3 is missing data which is odd as it is in the past.
Will raise a bug feedback