There is no scheduled drop in the SREC. It is just basic market behavior that if a utility has two choices to meet the RPS - buy an SREC or pay the SACP, they will not pay more for an SREC than the SACP. So, it is not theoretically impossible for SREC > SACP, but there is fundamentally no reason why it would be. (The only reason would be a fundamental change in the market such that non-MD entities wanted to buy the SRECs for other purposes, but I see nothing like that on the horizon.)But looking at this site Flett Exchange | Maryland Bill Will Raise the Price Cap for MD SRECs which shows your refferenced chart, it says the the cost of SREC's should not be effected by the SCAP's decreased number. but again time will tell i guess. I just dont know where you found any "scheduled" drop in SREC's because i cant find that anywhere.
And the quote is
The same bill also decreases the amount of solar that the energy companies have to procure. Taking into account the amount of solar installed in Maryland and the growth rate this should not have an effect on solar owner’s prices of their SRECs. The only way it will is if an unexpected amount of solar is installed in the next few years.
What they are saying is that the decrease in the RPS will not cause SREC prices to drop significantly below the SACP number for the given year because utilities are not likely to have other ways to make the even the lower RPS number in the bill (barring the "unexpected amount of solar" being installed) - they will still need to buy all our SRECs to avoid the SACP. What they are not suggesting is that SREC prices will be above the SACP for a given year, only that the lowering of the RPS number should not cause SREC prices to tank. (And this is a legitimate concern as MD had this happen several years ago.)
In the end, as @jjrandorin said, it may well make sense to look elsewhere. Even if factoring in a proper understanding of the value of an SREC and Tesla's lower pricing gets you a better deal than others, I would also have a concern about the REC agreement for the reasons you outlined. Additionally (unless covered elsewhere) it is not clear whether you have any obligation to keep the system for any length of time (suppose, for example, in 10 years the technology/price makes it worth replacing, or there is a fire in 5 years and you elect to replace with a different vendor.) And, it doesn't mention property transfers. Just as solar leases can be a sticking point in a home sale, this could potentially be an obligation that would be transferred with a sale.