How many stitches did you start out with in row 21? Without seeing the pattern, I would say yes. Count the dc and the chain 1, maybe even the sl st.

I didn't count. But I thought I should have 44 chain spaces.

Here's the beginning of the pattern for the back panel.

row 1: dc into third ch from hook and each ch to end (89 dc incl turning ch)

row 2: ch 2, dc into first 2 dc, *ch1, skip 1 st, dc into next st. repeat from * across. dc in turning ch. turn (44 ch spaces)

row 3-21: ch 2, dc into next dc and next ch sp, *ch 1, skip dc, dc into next ch sp, repeat from * ending with dc in turning ch. turn.

Interesting. I must be off a bit, but I come out with a few too many stitches after row 41. You work 89 sts on rows 1 to 21. You decrease 4 stitches at the beginning of row 22 and each following row through row 41. That's 20 rows of 4 st decreases, or 80 sts decreased. Wait a minute! The first time I did it, it came out be 40 sts decreased.

I see why you are confused!!! There's only one thing to do. More math. You started with 89 stitches on row 21. You want 43 stitches after row 41. 89 - 43 = 46 stitches to decrease over 20 rows or a bit more than 2 stitches per row. The decrease pattern for a fairly even decrease would be 2,2,3; 2,2,3; 2,2,3; 2,2,3; 2,2,3; 2,2,3; 2,2. It is a symmetrical decrease, right, tapering in on both sides?

Of course, this assumes that 43 sts is the correct target on row 41. How many inches is 43 sts according to the gauge? Does that match the pattern schematics?

(While you're on the topic of gauge, better check that yours is still the same as when you started. Mine, sadly, often wanders.)

I hope my arithmetic is good and that it all helps. Better double-check me.

Does this pattern come from a magazine? If so you may want to check their site for any corrections to the pattern. I've had to do that several times.