Thanks for sharing your solution, and for reminding me of the good old days on the PHP golf course. After digging out my old notes, I can finally share my PHP solutions too.

I had many different 173 strokers, such as (without bothering with the routine PHP bitwise ~ string inversion golfing trick to reduce the " on the wall" strings below by one char - see here or the "Quoted Strings" section at The golf course looks great, my swing feels good, I like my chances (Part VI) for the gory details of this PHP trick):

<?for(;$c=($b=++$n." bottle$s of beer")." on the wall",99^$x="$c, $b.
$z$x";$s=s)$z="Take one down and pass it around, $c.

";echo$x."Go to the store and buy some more, $c.";

<?for(;$c=($b=++$n." bottle$z[20] of beer")." on the wall",99^$x="$c, 
+$b.
$z$x";)$z="Take one down and pass it around, $c.

";echo$x."Go to the store and buy some more, $c.";

<?for(;99^$x=($c=($b=++$n." bottle$x[21] of beer")." on the wall").", 
+$b.
$x";$x="Take one down and pass it around, $c.

$x")?><?=$x,"Go to the store and buy some more, $c.";
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After I had given up, ToastyX mercifully gave me a hint, and then I finally did get to 172 -- but did not submit either of these two below because I would never have thought of them without ToastyX's hint:

<?for(;99^$c=($b=++$n." bottle$x[21] of beer")." on the wall";$x="
Take one down and pass it around, $c.

$c, $b.$x")?><?="$c, $b.$x
Go to the store and buy some more, $c.";

<?for(;99^$c=($b=++$n." bottle$s of beer")." on the wall";$s=s)$x="
Take one down and pass it around, $c.

$c, $b.$x";echo"$c, $b.$x
Go to the store and buy some more, $c.";
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