it is not supported to have more than 4 custom charset... there are several reasons for that (performance, GPU-related reasons etc)...
There may be some rare cases where you *really* need that feature... but also there in most cases having a custom charset that include a little bit more chars (e.g. merge - the smallest - 2 of your 5 custom charsets or similar) shouldn't hurt much...
There may also some other things you could do... depending on the details of what you want to do ... just one example:
for instance in some cases you could split your "mask" into 2 or more smaller mask and use those in e.g. a .hcmask file (https://hashcat.net/wiki/doku.php?id=mas...mask_files ...)
What you can/should do really depends on how your masks look like... but you will find a "workaround" (see wiki and forum)
There may be some rare cases where you *really* need that feature... but also there in most cases having a custom charset that include a little bit more chars (e.g. merge - the smallest - 2 of your 5 custom charsets or similar) shouldn't hurt much...
There may also some other things you could do... depending on the details of what you want to do ... just one example:
for instance in some cases you could split your "mask" into 2 or more smaller mask and use those in e.g. a .hcmask file (https://hashcat.net/wiki/doku.php?id=mas...mask_files ...)
What you can/should do really depends on how your masks look like... but you will find a "workaround" (see wiki and forum)