I had similar frustrations this morning. I called Roundabout last month and asked when exactly the Access10 tix would go onsale for Caroline or Change, and they told me in no uncertain terms, that they would go onsale this morning, the same day as Birthday Candles. I put it in my calendar and didn't question it. Only this morning, when I spoke to a representative on the phone, did I learn they went onsale a week and a half ago along with the regular tickets. Luckily we snagged Access10 for Birthday Candles this morning.
One upside is that I learned a bit more about the timing of the sales: apparently, the reason they had been staggering the Access10 date with the general public sales date (like with Rose Tattoo and Scotland PA), was because their in-person box office isn't open during the summer, and they didn't want to sell Access10 tickets online when the box office wasn't open in person (not exactly sure why). So for fall shows, the dates might be staggered, but for winter/spring shows, the Access10 date will be the same as general public sales.