You only "lose interest" on the high yield account if you withdraw early, the other account still accrues interest hourly, it's just how it is reported on the website that has changed.
That's correct.
Ask them to make this happen weekly though (the update). To break it down in an easier to understand model, let's assume an interest rate of 30% per month (1%/day).
I have 100 BTC. After 29 days, I have 129 BTC (we're excluding compound interest). I make a withdrawal of the full amount I see (100 BTC). Tomorrow I wake up to find that I have 29.29 BTC (29 left over + the .29 interest on that), leaving me with over 29 BTC left behind.
This is just a horrible model. It ensures that you can never withdraw everything -- by its very nature, you are forced to leave a balance in perpetuity. It makes no sense, and ADDS to the overhead since every single user that has ever used the service will always have cycles being used on their abandoned balances.
I was wrong at first by stating that users won't be able to see how much interest they have earned until a full month has passed. After further communication with the tech, I was assured that users still can see the interest added to their balance hourly - no change at all in this regard.
The only change is that you won't be able to withdraw the interest, as opposed to the principal, until a full month has passed.
To use your scenario, assume that the month has 30 days. On the 30th day, you will only be able to withdraw 100 BTC even though your balance indicates that you have about 130 BTC. You will be able to withdraw everything at 8:00 am of the following month, that is 100+30 BTC (about).
You won't leave anything in your HaoBTC account except maybe a negligible amount.