Avoid "+- 1" at every maskbits

engine/events/battle_tower/load_trainer.asm

@@ -27,12 +27,12 @@ Function_LoadOpponentTrainerAndPokemons: ; 1f8000
 	add b
 	ld b, a ; b contains the nr of the trainer
 if DEF(_CRYSTAL11)
-	maskbits BATTLETOWER_NUM_UNIQUE_TRAINERS +- 1
+	maskbits BATTLETOWER_NUM_UNIQUE_TRAINERS
 	cp BATTLETOWER_NUM_UNIQUE_TRAINERS
 else
 ; Crystal 1.0 used the wrong constant here, so only the first 21
 ; trainers in BattleTowerTrainers can be sampled.
-	maskbits BATTLETOWER_NUM_UNIQUE_PKMN +- 1
+	maskbits BATTLETOWER_NUM_UNIQUE_PKMN
 	cp BATTLETOWER_NUM_UNIQUE_PKMN
 endc
 	jr nc, .resample
@@ -115,7 +115,7 @@ Function_LoadRandomBattleTowerPkmn: ; 1f8081
 	ld a, [hRandomAdd]
 	add b
 	ld b, a
-	maskbits BATTLETOWER_NUM_UNIQUE_PKMN +- 1
+	maskbits BATTLETOWER_NUM_UNIQUE_PKMN
 	cp BATTLETOWER_NUM_UNIQUE_PKMN
 	jr nc, .resample
 	; in register 'a' is the chosen Pkmn of the LevelGroup

engine/events/buena.asm

@@ -17,7 +17,7 @@ Special_BuenasPassword: ; 8af6b
 	ld a, [MenuSelection]
 	ld c, a
 	ld a, [wBuenasPassword]
-	maskbits NUM_PASSWORDS_PER_CATEGORY +- 1
+	maskbits NUM_PASSWORDS_PER_CATEGORY
 	cp c
 	jr nz, .wrong
 	ld b, $1

engine/events/fish.asm

@@ -80,7 +80,7 @@ rept 4
 endr
 
 	ld a, [TimeOfDay]
-	maskbits NUM_DAYTIMES +- 1
+	maskbits NUM_DAYTIMES
 	cp NITE_F
 	jr c, .time_species
 	inc hl

engine/events/magnet_train.asm

@@ -435,7 +435,7 @@ MagnetTrain_Jumptable_FirstRunThrough: ; 8ceae
 	ld a, [wEnvironment]
 	push af
 	ld a, [TimeOfDay]
-	maskbits NUM_DAYTIMES +- 1
+	maskbits NUM_DAYTIMES
 	ld [TimeOfDayPal], a
 	ld a, $1
 	ld [wEnvironment], a

engine/events/poisonstep_pals.asm

@@ -10,7 +10,7 @@ LoadPoisonBGPals: ; cbcdd
 	and a
 	jr nz, .cgb
 	ld a, [TimeOfDayPal]
-	maskbits NUM_DAYTIMES +- 1
+	maskbits NUM_DAYTIMES
 	cp DARKNESS_F
 	ld a, %00000000
 	jr z, .convert_pals