I wouldn't go as far as to say it's completely flawed, but allow me to illustrate this via an example using R30 leve's.

30 * 1-star
30 + 3 ** 2-stars
30 + 6 *** 3 - stars
30 + 9 **** 4 - stars
40 * Next camp - 1 star

29 (chain bonus) <-- start doing R30 leve's or 4-star R20's
30 (chain bonus)
31 (no bonus) <-- I'd still do R30 leve
32 (chain bonus) <-- I'd do 2-star R30 now
33 (chain bonus)
34 (no bonus) <--- still doing 2-star R30 leve
35 (chain bonus) <--- 3-star R30
36 (chain bonus)
37 (no bonus)
38 (chain bonus) <--- 4-star R30
39 (chain bonus)
40 (chain bonus possible) <--- 1-star R40

-------------------------------------------------------------------------------

From this example there is three spots where you wouldn't have the ideal level to get the chain bonus exp, although its still entirely possible. At level 31, 34, and 37... however its still possible for a level 31 to take on level 33 but it might take too long to get the exp bonus, the same would go for 34 and 37. But factor in having a duo partner and this is easily doable.

Short post.... sorry leaving work