Senate President Therese Murray said of the fiscal 2013 House budget last weekend: “They have these very large amendments so I really don’t know everything that’s in there.”

That makes six million of us.

Murray was speaking specifically about a House clampdown on inappropriate use of welfare dollars by public aid recipients, but could have been referencing any number of issues or provisions settled behind the closed doors of Room 348, the specifics a mystery no doubt to many of the representatives who okayed them, nevermind the Senate and the rest of Massachusetts.

But the mystification of the Senate didn’t end there, as House leaders announced a sudden shift in approach to one of the key elements of the Beacon Hill agenda for 2011-12: new policies on health care cost control, a crucial determinant of fiscal and business robustness in Massachusetts as elsewhere.

After an extended stay in the Committee of Health Care Financing, the cost containment bill Gov. Deval Patrick filed in February of 2011 was sent verbatim to the Senate. This was the last thing anyone expected; it was assumed the modern rules of engagement were in effect: the committee chairs would negotiate out of sight, “pre-conferencing” as many areas of disagreement as possible, and then each branch would pass its version, probably late in the session to keep opportunity for public scrutiny, opposition, and floor debate to a minimum. Then the differences that did exist could either be worked out during a quick stay in conference, or settled more informally with more behind-the-scenes wrangling and quick amendment approval on the floor.

But wait. What actually happened is that the bill was sent right out to the Senate, untouched, from the committee where it had spent 14 months. Asked why the committee made no changes at all to an intricate, delicate, vital policy matter not devoid of controversy, House Chairman Steven Walsh of Lynn facetiously chose the absolute least plausible rationale: “Well, according to the governor it’s because it’s so perfect.” And Walsh said the Senate had requested the release of the governor’s bill.

But Murray again expressed bewilderment – not so much perhaps that the bill was being released, but that Walsh would publicly ascribe the release to the Senate’s request: “The chairman, I’m surprised would make a statement like that,” she said.

At that point veteran Beacon Hill hands knew something was afoot, and it took but two days for “something” to take shape. Having sent the original measure off to whatever fate the Senate chooses, House leaders announced they did indeed have a health-cost proposal ready – and they did so at the all-but-unheard of hour of 2:30 on Friday afternoon. It was the first anyone had heard about a discrete House piece of legislation intended for passage without reference to the Senate’s intentions. Indeed, House Speaker Robert DeLeo said he didn’t know what the Senate would do.

Murray responded that the Senate would stick to its original plan, and take up health-cost containment in mid-May, after rolling out its version next week. The dissonance could be a sign of an unusual level of discord between the branches on policy approach and that may not bode well for passage of any substantial reform at all.

In the midst of this to-and-fro stood Senate Health Care Chairman Richard Moore, whose comments had the tennis-match to-and-fro that legislators sometimes get caught in when squabbling erupts in the high councils of the two branches. Moore told the News Service Thursday morning that he hadn’t heard of any intention by House leaders to advance their own health-cost bill. But after Speaker DeLeo announced exactly such intentions Thursday afternoon, Moore said, “I’ve known that this was going to happen for over a week.” Advocates of cost reform were left to ponder the validity of Moore’s final assertion about inter-branch comity on the measure: “We’re on the same page.” Walsh said as much as well on Friday. It may just be that the branches have different ideas.

For the record, Walsh said his plan can squeeze $160 billion from the health care sector over 15 years without rate regulation and through, as he put it, a “gentle push” from state government to focus more on patient care, wellness, and coordination and less on fragmented care and an overreliance on testing. Pretty big savings if it works.

The zigging and zagging on health costs came in the context of yet another surprise: actual honest to goodness good news about medical inflation. Small-group rate hikes requested by the state’s health insurers averaged 0.7 percent in the third quarter – a far and cheerful cry from the days of routine double-digit increases in health insurance costs, and part of a recent trend. The Patrick administration took some credit, saying a 2010 law that expanded plan options, increased state oversight of insurance administration, and allowed more access to group-health purchasing. The administration also famously rejected and renegotiated a set of rate filings in the spring of 2010.